Ultrasonic 3D printing device and method

Abstract

The invention relates to an ultrasonic 3D printing device and method.The device comprises a signal generator, a power amplifier, two self-focusing ultrasonic transducers, a construction chamber, a hydrophone and an oscilloscope, the signal generator is connected with the power amplifier, the power amplifier is connected with the two self-focusing ultrasonic transducers, collimators are installed on the self-focusing ultrasonic transducers, and the construction chamber is connected with the hydrophone; the two self-focusing ultrasonic transducers are arranged in a bilateral symmetry mode and rotationally installed on the printing head movement driving mechanism in the construction chamber through the two mechanical arm mechanisms, so that the two self-focusing ultrasonic transducers are controlled to be confocal through the mechanical arm mechanisms to form the ultrasonic printing head. And the formed ultrasonic printing head is driven by the printing head movement driving mechanism to move so as to carry out ultrasonic 3D printing, and the oscilloscope is connected with the construction chamber through the hydrophone. According to the device and the method, the layering-free and high-strength 3D printing piece can be printed, the printing speed is high, the printing resolution ratio is high, the controllability is high, operation is easy, and the printing cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to an ultrasonic 3D printing device and method. Background Art

[0002] The energy sources used in existing 3D printing technologies are mainly light and heat, but light and heat cannot fully utilize all chemical potential in terms of controlling parameters. 3D printing of optically cured thermosetting materials can be achieved through methods such as SLA and LCD. However, due to the difficulty in applying very short heating and cooling rates in small local areas, effective on-demand curing of thermosetting polymers has not yet been introduced. Sonochemistry can be a solution for printing such materials because it has highly localized temperatures and fast heating and cooling rates. Acoustic-assisted manufacturing has been studied to a certain extent, but these studies were conducted in ultrasonic baths or horns, lacking highly concentrated reaction areas and high polymerization rates, which are required for 3D printing.

[0003] In addition, existing 3D printing technologies use light to achieve selective photopolymerization in the volume of optically transparent ink. However, the light attenuation of the ink itself, as well as the presence of already cured parts, limits the material selection and build size of light-based 3D printing. Although infrared light can be used to increase light penetration to several millimeters, it remains a technical challenge to penetrate light deeply into optically scattering media (such as biological tissue). Therefore, the application of existing 3D printing methods in deep penetration manufacturing solutions and minimally invasive manufacturing solutions has inherent limitations; the existing methods using light and heat as excitation sources are mainly based on the curing effect of the laser on the surface printing material during the printing process, so it is necessary to ensure that there is no medium that is opaque to the light source between the laser source and the printing material. Summary of the invention

[0004] The object of the present invention is to provide an ultrasonic 3D printing device and method, which can print out 3D printed parts without delamination and good strength, with fast printing speed, high printing resolution, strong controllability, easy operation and low printing cost.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an ultrasonic 3D printing device, comprising a signal generator, a power amplifier, two self-focusing ultrasonic transducers, a construction chamber, a hydrophone and an oscilloscope, wherein the signal generator is connected to the power amplifier, and the power amplifier is simultaneously connected to the two self-focusing ultrasonic transducers, and each self-focusing ultrasonic transducer is respectively installed with a collimator to make the ultrasonic beam more focused and directional, and the two self-focusing ultrasonic transducers are arranged symmetrically and rotatably installed on a print head motion driving mechanism in the construction chamber through two mechanical arm mechanisms, so that the two self-focusing ultrasonic transducers are controlled to have a common focal point to form an ultrasonic print head through the action of the two mechanical arm mechanisms, and the two self-focusing ultrasonic transducers and the formed ultrasonic print head are driven to move through the print head motion driving mechanism to perform ultrasonic 3D printing, and the oscilloscope is connected to the construction chamber through the hydrophone to assist in realizing the common focal point of the two self-focusing ultrasonic transducers by monitoring the sound wave signal.

[0006] Furthermore, the mechanical arm mechanism includes a mechanical support arm, a first swing mechanism and a second swing mechanism. The rear end of the mechanical support arm is installed on the print head motion drive mechanism through the first swing mechanism, and the self-focusing ultrasonic transducer is installed on the front end of the mechanical support arm through the second swing mechanism, so as to adjust the position and orientation of the self-focusing ultrasonic transducer by controlling the swing of the front and rear ends of the mechanical support arm, thereby realizing the confocal point of the two self-focusing ultrasonic transducers and adjusting the acoustic axis angle between the two self-focusing ultrasonic transducers to adjust the printing resolution.

[0007] Furthermore, the building chamber includes a shell, a water chamber, a printing dish, a printing platform, a printing platform motion drive mechanism, a robotic arm mechanism and a print head motion drive mechanism. The printing platform is arranged in the printing dish and installed on the printing platform motion drive mechanism to move under the drive of the printing platform motion drive mechanism. The robotic arm mechanism is installed on the print head motion drive mechanism to move under the drive of the print head motion drive mechanism.

[0008] Furthermore, it also includes a control unit, which is respectively connected to the signal generator, the power amplifier, the mechanical arm mechanism, the oscilloscope, and the print head motion drive mechanism and the printing platform motion drive mechanism in the building room to control the work of each part.

[0009] The present invention also provides an ultrasonic 3D printing method based on the above device, comprising: First, the imported model is analyzed and processed using CAM numerical control software to obtain printing parameters; the printing material is imported into the build chamber; The printing power is formed according to the printing parameters, and then the signal generator is turned on to emit a given sine wave signal, and then the power amplifier is turned on for impedance matching, and the corresponding printing power is adjusted to control the self-focused ultrasonic transducer to emit ultrasonic waves; The two self-focusing ultrasonic transducers are controlled to form a common focal point of an ultrasonic print head through the action of two mechanical arm mechanisms, and the common focal point position is the position of the formed ultrasonic print head; A printing path is formed according to the printing parameters, and then the print head motion driving mechanism is controlled to drive the formed ultrasonic print head to move along the printing path on the printing material, and an acoustic cavitation effect is applied to the printing material to perform ultrasonic 3D printing. The printing material passed by the ultrasonic print head is accelerated to solidify and form a component; After printing is completed, the cured component is removed from the uncured material.

[0010] Furthermore, during the ultrasonic 3D printing process, the liquid printing material is solidified by the acoustic cavitation effect and deposited onto the printing platform of the build chamber or on the upper part of the previously deposited and solidified area.

[0011] Furthermore, the two self-focusing ultrasonic transducers are controlled to form a common focus of an ultrasonic print head through the action of two mechanical arm mechanisms, and the implementation method is as follows: First, let the theoretical focal points of the two self-focusing ultrasonic transducers overlap, and then move the focus of the self-focusing ultrasonic transducers in a small area, monitor the sound wave signal through a hydrophone and an oscilloscope, and find the position where the waveform signal is the largest from the oscilloscope, which is the common focal point position.

[0012] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides an ultrasonic 3D printing device and method, which can print in some opaque materials and have better penetration depth than the traditional optical 3D printing method, and the sound waves emitted by the device and method have the advantages of adjustable center frequency, large sound wave spectrum bandwidth, higher printing resolution, more precise control of printing structure, etc., and at the same time, the results of ultrasonic printing have similar mechanical properties compared with the traditional thermal curing method. In addition, the present invention uses two self-focusing ultrasonic transducers to form an ultrasonic print head at the same focal point, and its center frequency is higher than that of a single transducer, the frequency response bandwidth is wider, and the acoustic diffraction limit of the focused sound beam is narrower, which improves the resolution of ultrasonic 3D printing, and can use continuous sound field printing of different frequencies, which can accurately control the longitudinal printing position and improve printing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of a device implementation principle of an embodiment of the present invention; Figure 2 is a schematic diagram of the internal structure of a building chamber in an embodiment of the present invention; Figure 3 1 is a simulation effect diagram of different acoustic axis angles in an embodiment of the present invention; Figure 4 4 is a graph showing the influence of different acoustic axis angles on the sound pressure and focal area in an embodiment of the present invention.

[0014] In the figure: 1-signal generator; 2-power amplifier; 3-self-focusing ultrasonic transducer; 4-building chamber; 5-hydrophone; 6-oscilloscope; 7-water chamber; 8-building chamber housing; 9-printing dish; 10-printing platform; 11-printing platform motion drive mechanism; 12-mechanical arm mechanism; 13-collimator; 14-print head motion drive mechanism; α-acoustic axis angle. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0016] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0017] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0018] like Figure 1-2 As shown, this embodiment provides an ultrasonic 3D printing device, including a signal generator 1, a power amplifier 2, two self-focusing ultrasonic transducers 3, a building chamber 4, a hydrophone 5 and an oscilloscope 6, wherein the signal generator 1 is connected to the power amplifier 2, and the power amplifier 2 is simultaneously connected to the two self-focusing ultrasonic transducers 3, and each self-focusing ultrasonic transducer 3 is respectively installed with a collimator 13 to make the ultrasonic beam more focused and directional, and the two self-focusing ultrasonic transducers 3 are arranged in a bilaterally symmetrical manner and are rotatably installed on a print head motion driving mechanism 14 in the building chamber 4 through two mechanical arm mechanisms 12, so that the two self-focusing ultrasonic transducers 3 are controlled to have a common focus to form an ultrasonic print head through the action of the two mechanical arm mechanisms 12, and the two self-focusing ultrasonic transducers 3 and the formed ultrasonic print head are driven to move through the print head motion driving mechanism 14 to perform ultrasonic 3D printing, and the oscilloscope 6 is connected to the building chamber 4 through the hydrophone 5 to assist in realizing the common focus of the two self-focusing ultrasonic transducers by monitoring the sound wave signal.

[0019] In this embodiment, the mechanical arm mechanism 12 includes a mechanical support arm, a first swing mechanism and a second swing mechanism. The rear end of the mechanical support arm is installed on the print head motion drive mechanism through the first swing mechanism, and the self-focusing ultrasonic transducer is installed on the front end of the mechanical support arm through the second swing mechanism, so as to adjust the position and orientation of the self-focusing ultrasonic transducer by controlling the swing of the front and rear ends of the mechanical support arm, thereby realizing the confocal point of the two self-focusing ultrasonic transducers and adjusting the acoustic axis angle between the two self-focusing ultrasonic transducers to adjust the printing resolution.

[0020] It should be noted that this device combines a self-focusing ultrasonic transducer with an ultrasonic collimator, that is, a collimator is added in front of the self-focusing transducer. The addition of the collimator can make the ultrasonic beam more focused and directional, reduce the divergence and scattering of the beam, and greatly improve the utilization rate of acoustic energy; by blocking unnecessary ultrasonic signals, the sidelobe effect and noise interference are reduced; the collimator can accurately focus the ultrasonic energy to the lesion site, ensure that the focal position obtains sufficient energy, improve the effectiveness of printing, and at the same time minimize the disturbance to the surrounding medium and reduce the risk of solidifying non-target areas.

[0021] In this embodiment, the build chamber 4 includes a shell 8, a water chamber 7, a printing dish 9, a printing platform 10, a printing platform motion drive mechanism 11, a robotic arm mechanism 12 and a print head motion drive mechanism 14. The printing platform 10 is arranged in the printing dish 9 and installed on the printing platform motion drive mechanism 11 to move under the drive of the printing platform motion drive mechanism. The robotic arm mechanism 12 is installed on the print head motion drive mechanism 14 to move under the drive of the print head motion drive mechanism.

[0022] In this embodiment, the ultrasonic 3D printing device also includes a control unit, which is respectively connected to the signal generator, the power amplifier, the robotic arm mechanism, the oscilloscope, and the print head motion drive mechanism and the printing platform motion drive mechanism in the building chamber to control the operation of each part.

[0023] This embodiment also provides an ultrasonic 3D printing method based on the above device, including: S1. First, use CAM numerical control software to analyze and process the imported model to obtain printing parameters; import the printing material into the build room.

[0024] S2. The printing power is formed according to the printing parameters, and then the signal generator is turned on to emit a given sinusoidal wave signal. Then, the power amplifier is turned on for impedance matching, and the corresponding printing power is adjusted to control the self-focusing ultrasonic transducer to emit ultrasonic waves.

[0025] S3. Control two self-focusing ultrasonic transducers to have a common focal point to form an ultrasonic print head through the actions of two mechanical arm mechanisms. The common focal point position is the position of the formed ultrasonic print head.

[0026] First, determine the resolution required for printing, and then adjust the acoustic axis angle between the two transducers through the action of the two mechanical arm mechanisms 12. Since the acoustic focus is formed by the interference of two ultrasonic beams, the precise alignment of the two beams is crucial. First, let the theoretical focus of the two self-focusing ultrasonic transducers overlap, and then let the focus of the self-focusing ultrasonic transducers move in a small area, monitor the acoustic wave signal through the hydrophone and oscilloscope, and find the position with the largest waveform signal from the oscilloscope, which is the common focus position, to ensure that the actual position is accurate.

[0027] When determining the printing resolution, the printing accuracy and printing efficiency should be considered comprehensively. A high resolution means high printing accuracy but low printing efficiency; a low resolution means low printing accuracy but high printing efficiency.

[0028] S4, forming a printing path according to the printing parameters, and then controlling the movement of the print head drive mechanism to drive the formed ultrasonic print head to move along the printing path on the printing material, applying the acoustic cavitation effect to the printing material to perform ultrasonic 3D printing, and the printing material passed by the ultrasonic print head is accelerated to solidify and form a component. The liquid printing material is solidified by the acoustic cavitation effect and deposited on the printing platform of the build chamber or on the upper part of the previously deposited and solidified area.

[0029] S5. After printing is completed, the cured component is taken out from the uncured material.

[0030] The present invention solves the problem that existing 3D printing technology cannot print materials with poor photosensitivity and cannot print through media, and provides an ultrasonic 3D printing device and method. At the same time, through the design of the confocal point of a dual self-focusing ultrasonic transducer, the printing resolution can be improved and the implementation cost of the printing equipment can be reduced. As a mechanical wave, sound waves have a wide wavelength coverage range and a relatively low frequency (relative to light waves). The sound wave energy can pass through most media to reach the working plane. Based on these characteristics of sound waves, a sonochemical reaction is generated locally in the printed material through a high-energy focused sound field to achieve acoustic 3D printing. Printing can be performed inside the penetrating medium, and structures with different porosities can also be printed.

[0031] In the present invention, the electrical signal generated by the signal generator 1 is amplified by the power amplifier 2, and the ultrasonic field generated by the self-focused ultrasonic transducer 3 is driven to reach the printing material after passing through the shell of the building chamber. At the confocal position in the printing material, the chemically active acoustic cavitation area solidifies the liquid printing material (resin or mixture, etc.) and deposits it on the printing platform, or on the top of the previously deposited and solidified area. We call this area a super-active micro-reaction area, where the generated bubbles and polymerized resin appear in the low-pressure area, and then they migrate to the high-pressure area instantaneously until they reach the platform or the previously solidified pixel, where they are deposited. The transducer movement is controlled by the print head motion drive mechanism to locate the focus area along the calculated path in the building chamber, thereby creating the designed part point by point. The stability of the acoustic signal output during the process is observed by the hydrophone 5 and the oscilloscope 6.

[0032] However, if a single high-energy focused transducer is used, its central frequency response bandwidth is narrow and the acoustic diffraction limit of the focused sound beam is wide, resulting in insufficient limit lateral resolution of printing. In addition, the use of single-frequency continuous sound field printing will make it impossible to accurately control the longitudinal printing position, thereby reducing printing accuracy. Therefore, the present invention innovatively designs two high-intensity ultrasonic transducers so that the ultrasonic parameters / excitation parameters (frequency, pulse width, pulse repetition frequency, etc.) in the acoustic printing area can be synchronized and controlled by a signal generator. By changing the focus shape and size in a confocal manner and controlling the acoustic energy intensity, objects with different focal sizes (ie, resolutions) can be printed, and the lateral resolution is increased, providing more precise control over the printing process. Different acoustic axis angles between transducers will result in different focal areas and focal acoustic energies. The simulation effect is as follows: Figure 3 , 4 shown.

[0033] By crossing the beams of two self-focusing ultrasonic transducers, the axial focal size and focal volume can be significantly reduced. The overlapping area of ​​the two sound waves forms a new focal spot, and the resulting focal area is greatly reduced compared to the single transducer mode. Another important advantage of this device is that the ultrasonic beam intensity required for each transducer in the dual transducer is smaller than that of a single transducer, which can significantly reduce the cost of the equipment. In addition, since the parameters of each transducer in the dual transducer are greatly reduced compared to a single transducer, the device can also significantly reduce the medium disturbance on the original sound wave path.

[0034] Simulation analysis: In the finite element simulation, let's take a few examples. When the acoustic axis angle is 45°, as the phase moves from in-phase to out-of-phase, the intensity of the single main focal lobe decreases and splits into two side lobes. We confirmed a similar phenomenon when the acoustic axis angle is 60°. In contrast, when the acoustic axis angle is 90°, there are two side lobes on both sides of the main lobe even under in-phase conditions, but the intensity and shape of this pattern do not change significantly as the focus misalignment increases. Therefore, due to the presence of side lobes, the lateral resolution of the 90° angle case is poorer than that of the 45° and 60° angles, but the 90° angle as the acoustic axis angle has the highest axial resolution and robustness to errors caused by miscalibration. Therefore, different angles have different advantages and disadvantages, usage scenarios, and resolutions.

[0035] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. An ultrasonic 3D printing device, characterized in that: The invention comprises a signal generator, a power amplifier, two self-focusing ultrasonic transducers, a construction chamber, a hydrophone and an oscilloscope, wherein the signal generator is connected to the power amplifier, and the power amplifier is simultaneously connected to the two self-focusing ultrasonic transducers, and each self-focusing ultrasonic transducer is respectively installed with a collimator to make the ultrasonic beam more focused and directional, and the two self-focusing ultrasonic transducers are arranged symmetrically and rotatably installed on a print head motion driving mechanism in the construction chamber through two mechanical arm mechanisms, so that the two self-focusing ultrasonic transducers are controlled to have a common focal point to form an ultrasonic print head through the action of the two mechanical arm mechanisms, and the two self-focusing ultrasonic transducers and the formed ultrasonic print head are driven to move through the print head motion driving mechanism to perform ultrasonic 3D printing, and the oscilloscope is connected to the construction chamber through the hydrophone to assist in realizing the common focal point of the two self-focusing ultrasonic transducers by monitoring the sound wave signal.

2. The ultrasonic 3D printing device according to claim 1, characterized in that: The mechanical arm mechanism includes a mechanical support arm, a first swing mechanism and a second swing mechanism. The rear end of the mechanical support arm is installed on the print head motion drive mechanism through the first swing mechanism, and the self-focusing ultrasonic transducer is installed on the front end of the mechanical support arm through the second swing mechanism, so as to adjust the position and orientation of the self-focusing ultrasonic transducer by controlling the swing of the front and rear ends of the mechanical support arm, thereby realizing the confocal point of the two self-focusing ultrasonic transducers and adjusting the acoustic axis angle between the two self-focusing ultrasonic transducers to adjust the printing resolution.

3. The ultrasonic 3D printing device according to claim 1, characterized in that: The building chamber includes a shell, a water chamber, a printing dish, a printing platform, a printing platform motion drive mechanism, a mechanical arm mechanism and a print head motion drive mechanism. The printing platform is arranged in the printing dish and installed on the printing platform motion drive mechanism to move under the drive of the printing platform motion drive mechanism. The mechanical arm mechanism is installed on the print head motion drive mechanism to move under the drive of the print head motion drive mechanism.

4. The ultrasonic 3D printing device according to claim 1, characterized in that: It also includes a control unit, which is respectively connected to the signal generator, the power amplifier, the mechanical arm mechanism, the oscilloscope, and the print head motion drive mechanism and the print platform motion drive mechanism in the building chamber to control the work of each part.

5. An ultrasonic 3D printing method based on the device according to any one of claims 1 to 4, characterized in that: include: First, CAM numerical control software is used to analyze and process the imported model to obtain printing parameters; Importing printing materials into the build chamber; The printing power is formed according to the printing parameters, and then the signal generator is turned on to emit a given sine wave signal, and then the power amplifier is turned on for impedance matching, and the corresponding printing power is adjusted to control the self-focused ultrasonic transducer to emit ultrasonic waves; The two self-focusing ultrasonic transducers are controlled to form a common focal point of an ultrasonic print head through the action of two mechanical arm mechanisms, and the common focal point position is the position of the formed ultrasonic print head; A printing path is formed according to the printing parameters, and then the print head motion driving mechanism is controlled to drive the formed ultrasonic print head to move along the printing path on the printing material, and an acoustic cavitation effect is applied to the printing material to perform ultrasonic 3D printing. The printing material passed by the ultrasonic print head is accelerated to solidify and form a component; After printing is completed, the cured component is removed from the uncured material.

6. The ultrasonic 3D printing method according to claim 5, characterized in that: During ultrasonic 3D printing, liquid printing material is solidified by the acoustic cavitation effect and deposited onto the printing platform of the build chamber or on top of a previously deposited and solidified area.

7. The ultrasonic 3D printing method according to claim 5, characterized in that: The two self-focusing ultrasonic transducers are controlled by the action of the two mechanical arm mechanisms to form a common focus of the ultrasonic print head, and the implementation method is as follows: First, let the theoretical focal points of the two self-focusing ultrasonic transducers overlap, and then move the focus of the self-focusing ultrasonic transducers in a small area, monitor the sound wave signal through a hydrophone and an oscilloscope, and find the position where the waveform signal is the largest from the oscilloscope, which is the common focal point position.

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