Focused ultrasonic printing device and method

Abstract

The invention relates to a focused ultrasonic printing device and method, and belongs to the technical field of additive manufacturing, and the device comprises a driving assembly which is used for providing a stable ultrasonic signal; the printing assembly comprises a focusing transducer, a water tank, an ink box, a deposition plate and a three-dimensional movement mechanism; the focused transducer is located in the water tank and used for receiving the ultrasonic signals provided by the driving assembly and generating a high-precision focused ultrasonic field. The water tank is positioned below the ink box; the deposition plate is located in the ink box and used for depositing a printing target. The three-dimensional movement mechanism is used for controlling the movement track of the deposition plate; and the control assembly is used for obtaining ultrasonic printing parameters and controlling the driving assembly and the three-dimensional movement mechanism. The device can realize high-precision printing of complex geometric structures.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and particularly to a focused ultrasound printing device and method. Background Art

[0002] In recent years, great progress has been made in additive manufacturing technology both in terms of printing materials and printing processes. However, light and heat are still the only energy sources used to drive polymer chemical reactions or physical transformations in additive manufacturing. Among them, stereolithography (SLA / DLW) cures photosensitive resin layer by layer through laser or ultraviolet light, with limited material selection (only applicable to photocurable materials) and limited penetration depth (<1 mm); thermal curing technology (FDM / SLS) relies on the melting-solidification process of thermoplastic materials and requires a build platform support, making it difficult to achieve deep printing of complex geometric structures. Traditional ultrasonic polymerization uses an ultrasonic bath or a horn reactor, which can only produce a dispersed cavitation effect and cannot achieve spatial selective polymerization. Summary of the Invention

[0003] In view of one or more technical problems existing in the prior art, the present invention provides a focused ultrasound printing device and method, which can achieve high-precision printing of complex geometric structures.

[0004] In a first aspect, the present invention provides a focused ultrasound printing device, comprising:

[0005] A driving component for providing a stable ultrasonic signal;

[0006] A printing component including a focused transducer, a water tank, an ink cartridge, a deposition plate, and a three-dimensional motion mechanism; the focused transducer is located inside the water tank and is used to receive the ultrasonic signal provided by the driving component and generate a high-precision focused ultrasound field; the water tank is located below the ink cartridge; the deposition plate is located inside the ink cartridge and is used to deposit printing targets; the three-dimensional motion mechanism is used to control the motion trajectory of the deposition plate;

[0007] A control component for obtaining parameters of ultrasonic printing and controlling the driving component and the three-dimensional motion mechanism.

[0008] Preferably, the driving component includes a power amplifier and an impedance matcher.

[0009] Preferably, the control component includes an operation screen, a host computer, and a slave computer;

[0010] The host computer is used to obtain printing parameters of a printing model and feedback the printing parameters to the slave computer;

[0011] The slave computer is used to control the power amplifier and the three-dimensional motion mechanism according to the received printing parameters.

[0012] Preferably, the three-dimensional motion mechanism includes an X-axis motion mechanism, a Y-axis motion mechanism, and a Z-axis motion mechanism.

[0013] Preferably, the ink cartridge is slidably disposed on the X-axis motion mechanism; or

[0014] The ink cartridge is fixed by a bracket disposed inside the water tank, and the deposition plate is fixed on the Z-axis motion mechanism.

[0015] In a second aspect, the present invention provides a focused ultrasound printing method, which is implemented by the device described in the first aspect. The printing method includes:

[0016] Construct a printing model;

[0017] Perform model slicing and determine the parameters of focused ultrasound printing; the parameters include the scanning path of the focused focal point, the scanning speed, the filling density, and the sound pressure amplitude;

[0018] Perform focused ultrasound printing using ink.

[0019] Preferably, during the focused ultrasound printing process, the scanning speed of the focused focal point is 0.4 to 8 mm / s, the filling density is 30 to 100%, and the sound pressure amplitude is 20 to 100 MPa.

[0020] In a third aspect, the present invention provides a focused ultrasound printing ink, which can realize the forming of a complex geometric structure by the device described in the first aspect. The ink includes a polymerizable monomer, an initiator, and nano-hydroxyapatite;

[0021] The polymerizable monomer includes an acrylic monomer and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide; the molar ratio of the acrylic monomer to [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide is 1 to 5:1;

[0022] The dosage of the nano-hydroxyapatite is not less than 30% of the mass of the polymerizable monomer.

[0023] Preferably, the dosage of the nano-hydroxyapatite is 30 to 100% of the mass of the polymerizable monomer; and / or

[0024] The dosage of the initiator is 0.05 to 0.5% of the mass of the polymerizable monomer; the initiator is preferably a radical initiator, and more preferably ammonium persulfate.

[0025] In a fourth aspect, the present invention provides a preparation method of the focused ultrasound printing ink described in the third aspect. The preparation method includes:

[0026] Mix acrylic monomers and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide to obtain a premixed solution;

[0027] Mix the premixed solution, initiator, and nano-hydroxyapatite, and after aging treatment and defoaming, obtain the ink for focused ultrasound printing.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] The focused ultrasound printing device provided by the present invention generates an ultrasonic signal by controlling the driving component. The focused transducer converts the received ultrasonic signal into a focused ultrasound field, and places the focused transducer inside the water tank to ensure efficient transmission of acoustic energy to the deposition plate; by controlling the three-dimensional motion mechanism to regulate the motion trajectory of the deposition plate (i.e., the scanning trajectory of the focused focus), to ensure that the acoustic-thermal effect is triggered in the focused focus area to promote the ultrasonic polymerization of the ink, and layer by layer stacking is achieved to realize high-precision printing of complex geometric structures.

[0030] The present invention first constructs a 3D printing model, then slices the model to obtain the forming data of each layer, determines the parameters of focused ultrasound printing, and finally performs focused ultrasound printing with the ink. Utilizing the acoustic energy and the tissue penetration characteristics of the sound wave, a spherical ultrasonic transducer is used to focus the sound field to a point, triggering the acoustic-thermal effect in the focus area to generate local high temperature, triggering the free radical polymerization of the polymerizable monomer, and realizing layer-by-layer printing by controlling the three-dimensional motion of the focused focus, and performing three-dimensional tissue reconstruction at specific positions.

[0031] The focused ultrasound printing method provided by the present invention has the deep printing ability to penetrate light-scattering media (>64 mm), can realize full-degree-of-freedom volume printing without constructing a platform, can directly form complex geometric structures with high resolution (0.3 - 0.7 mm), and can also support the rapid curing of thermosetting materials.

[0032] Using acrylic monomers and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide as polymerizable monomers in the present invention, an ink with acoustic-thermal conversion performance can be obtained. By introducing nano-hydroxyapatite, the viscosity of the ink can be effectively regulated to inhibit acoustic streaming disturbance, improve the resolution and printing accuracy, and can be used to form complex geometric structures with high resolution (0.3 - 0.7 mm). Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0034] Figure 1 It is a schematic structural diagram of a system for focused ultrasound printing provided by the present invention;

[0035] Figure 2 It is a schematic structural diagram of another system for focused ultrasound printing provided by the present invention;

[0036] Figure 3 It is a transmittance - temperature curve graph of the ink for focused ultrasound printing provided in Embodiments 3 - 6 and Comparative Examples 1 - 4 of the present invention;

[0037] Figure 4 It is a viscosity curve graph of the ink for focused ultrasound printing provided in Embodiment 3, Embodiments 7 - 9 and Comparative Example 5 of the present invention;

[0038] Figure 5 It is a picture of the Achilles tendon repair before and after focused ultrasound provided by the present invention;

[0039] Figure 6 It is a picture of bone tissue repair by focused ultrasound printing provided by the present invention.

[0040] Reference numerals: 1 - driving component; 11 - power amplifier; 12 - impedance matcher; 2 - printing component; 21 - focusing transducer; 22 - water tank; 23 - ink cartridge; 24 - deposition plate; 251 - X - axis movement mechanism; 252 - Y - axis movement mechanism; 253 - Z - axis movement mechanism; 26 - bracket; 3 - control component; 31 - operation screen; 32 - host computer; 33 - slave computer. Detailed Embodiments

[0041] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] The present invention provides a focused ultrasound printing device in the first aspect, as Figure 1 - Figure 2 shown, including:

[0043] A driving component 1 for providing a stable ultrasonic signal;

[0044] Printing component 2, including a focusing transducer 21, a water tank 22, an ink cartridge 23, a deposition plate 24, and a three-dimensional motion mechanism; the focusing transducer 21 is located inside the water tank 22 and is used to receive the ultrasonic signal provided by the driving component 1 and generate a high-precision focused ultrasound field; the water tank 22 is located below the ink cartridge 23; the deposition plate 24 is located inside the ink cartridge 23 and is used to deposit the printing target; the three-dimensional motion mechanism is used to control the motion trajectory of the deposition plate 24;

[0045] Control component 3, used to obtain the parameters of ultrasonic printing and control the driving component 1 and the three-dimensional motion mechanism.

[0046] The focused ultrasound printing device provided by the present invention generates an ultrasonic signal by controlling the driving component. The focusing transducer converts the received ultrasonic signal into a focused ultrasound field. The focusing transducer is placed inside the water tank to ensure efficient transmission of acoustic energy to the deposition plate. By controlling the three-dimensional motion mechanism to regulate the motion trajectory of the deposition plate (i.e., the scanning trajectory of the focused spot), it is ensured that the acoustic-thermal effect is triggered in the focused spot area to promote the ultrasonic polymerization of the ink, layer by layer stacking, to achieve high-precision printing of complex geometric structures.

[0047] According to some preferred embodiments, the driving component 1 includes a power amplifier 11 and an impedance matcher 12.

[0048] According to some preferred embodiments, the control component 3 includes a control screen 31, a host computer 32, and a slave computer 33;

[0049] The host computer 32 is used to obtain the printing parameters of the printing model and feedback the printing parameters to the slave computer 33;

[0050] The slave computer 33 is used to control the power amplifier 11 and the three-dimensional motion mechanism according to the received printing parameters.

[0051] In the present invention, the slave computer 33, the power amplifier 11, the impedance matcher 12, and the focusing transducer 21 are connected in sequence. The slave computer 33 drives the three-dimensional motion mechanism to move by controlling the servo motor. In the present invention, by inputting the printing parameters into the host computer 32 and transmitting them to the slave computer 33, the slave computer 33 generates an ultrasonic signal by controlling the power amplifier 11, and the ultrasonic signal is converted into a focused ultrasound field by the focusing transducer 21; the slave computer 33 drives the deposition plate 24 to move by controlling the three-dimensional motion mechanism, realizing layer-by-layer printing to obtain the printing target.

[0052] According to some preferred embodiments, the three-dimensional motion mechanism includes an X-axis motion mechanism 251, a Y-axis motion mechanism 252, and a Z-axis motion mechanism 253. By controlling the three-dimensional motion mechanism of the present invention, the deposition plate 24 can be moved in three-dimensional space to achieve high-precision printing of 3D structures. The X-axis motion mechanism 251 is an X-axis sliding guide rail. The Y-axis motion mechanism 252 includes two symmetrically arranged Y-axis sliding guide rails. The Z-axis motion mechanism 253 is disposed on the X-axis motion mechanism 251.

[0053] According to some preferred embodiments, the ink cartridge 23 is slidably disposed on the X-axis motion mechanism 251. The deposition plate 24 is disposed at the bottom of the ink cartridge 23. The ink cartridge 23 moves horizontally driven by the X-axis motion mechanism 251 and the Y-axis motion mechanism 252, and moves vertically driven by the Z-axis motion mechanism 253, thereby driving the deposition plate 24 to move and realizing the printing of the three-dimensional model.

[0054] According to some preferred embodiments, the ink cartridge 23 is fixed by a bracket 26 disposed inside the water tank 22, and the deposition plate 24 is fixed on the Z-axis motion mechanism 253. The deposition plate 24 can be moved in three-dimensional space driven by the X-axis motion mechanism 251, the Y-axis motion mechanism 252, and the Z-axis motion mechanism 253.

[0055] In some specific embodiments of the present invention, the focusing transducer is purchased from Haifu Company, with the model number H-148, the fundamental frequency adjustable to 3.85 MHz, the focal spot size of 0.8×5.33 mm (fundamental frequency), and the electroacoustic efficiency of 85%. The model number of the power amplifier is T&C Power AG0613, the output power is 5 - 210 W, and the duty cycle is adjustable from 10% to 90%. The model number of the upper computer is OrangePi 3B, and the model number of the lower computer is MKS Monster8 V2.0. The moving accuracy of the X-axis motion mechanism, the Y-axis motion mechanism, and the Z-axis motion mechanism is ±10 μm, and the printing size is 430×320×150 mm 3 . The water tank is filled with degassed deionized water (temperature 25±2°C); the ink cartridge is a film-encapsulated ink cartridge (PET film, 10 μm thick) for holding ink. It should be noted that the above components of the present invention are not limited to the above models and sizes, and can be selected and adjusted according to actual situations.

[0056] The present invention provides a focused ultrasound printing method in a second aspect, which is realized by the device described in the first aspect. The printing method includes:

[0057] Construct a printing model;

[0058] Perform model slicing and determine the parameters of focused ultrasound printing; the parameters include the scanning path of the focusing focus, the scanning speed, the filling density, and the sound pressure amplitude;

[0059] Focused ultrasound printing is carried out using ink.

[0060] In the present invention, a 3D printing model is first constructed, then the model is sliced to obtain the forming data of each layer, and the parameters of focused ultrasound printing are determined. Finally, focused ultrasound printing is carried out using ink. By utilizing the acoustic wave energy and the tissue penetration characteristics of the acoustic wave, a spherical ultrasonic transducer is used to focus the sound field to a point, triggering a thermoacoustic effect in the focal region to generate local high temperature, triggering the free radical polymerization of polymerizable monomers. By controlling the three-dimensional movement of the focused focal point, layer-by-layer printing is achieved, and three-dimensional tissue reconstruction is carried out at specific positions.

[0061] The focused ultrasound printing method provided by the present invention has the ability of deep printing that can penetrate light-scattering media (>64 mm), can achieve full-degree-of-freedom volume printing without constructing a platform, can directly form complex geometric structures with high resolution (0.3 - 0.7 mm), and can support the rapid curing of thermosetting materials by heat curing.

[0062] Specifically: In the present invention, the graphic and material data of the printing target are first processed through computer software (for example, SolidWorks software) to construct a printing model of a three-dimensional solid object to be printed (such as mechanical parts, biological organs, etc.), and the model is sliced (for example, using Meshmixer) into spheres, and the center coordinates of the spheres are extracted to slice and layer the three-dimensional solid object's solid model to generate layered G-code (layer height 0.5 - 1.25 mm), obtaining the forming data of each layer, determining the printing parameters, and finally carrying out focused ultrasound printing using ink to obtain the printing target. Among them, the scanning speed during the focused ultrasound printing process matches the curing rate of the ink; the filling density takes into account both the structural strength and the printing efficiency; the penetration depth is dynamically adjusted through the sound pressure amplitude; a suitable ultrasonic power can be selected according to the polymerization temperature of the ink.

[0063] According to some preferred embodiments, during the focused ultrasound printing process, the scanning speed of the focused focal point is 0.4 - 8 mm / s (for example, it can be 0.4 mm / s, 1 mm / s, 2 mm / s, 3 mm / s, 4 mm / s, 5 mm / s, 6 mm / s, 7 mm / s or 8 mm / s), the filling density is 30 - 100% (for example, it can be 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%), and the sound pressure amplitude is 20 - 100 MPa (for example, it can be 20 MPa, 30 MPa, 40 MPa, 50 MPa, 60 MPa, 70 MPa, 80 MPa, 90 MPa or 100 MPa).

[0064] The present invention provides a focused ultrasound printing ink in a third aspect. By using the device described in the first aspect, the formation of complex geometric structures can be achieved. The ink includes a polymerizable monomer, an initiator, and nano-hydroxyapatite; the polymerizable monomer includes an acrylic monomer and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide; the molar ratio of the acrylic monomer to [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide is 1 to 5:1; the dosage of the nano-hydroxyapatite is not less than 30% of the mass of the polymerizable monomer.

[0065] The present invention uses an acrylic monomer and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide as polymerizable monomers to obtain an ink with acoustic-thermal conversion performance. By introducing nano-hydroxyapatite, the viscosity of the ink can be effectively regulated to inhibit acoustic streaming disturbance, improve the resolution (0.3 - 0.7 mm) and printing accuracy, and can be used to form high-resolution complex geometric structures.

[0066] According to some preferred embodiments, the molar ratio of the acrylic monomer to [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide is 2 to 5:1.

[0067] According to some preferred embodiments, the dosage of the nano-hydroxyapatite is 30 - 100% of the mass of the polymerizable monomer (for example, it can be 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100%).

[0068] The dosage of the initiator is 0.05 - 0.5% of the mass of the polymerizable monomer; the initiator is preferably a radical initiator, and more preferably ammonium persulfate.

[0069] The polymerization temperature of the ink for focused ultrasound printing in the present invention is 60 - 150 °C.

[0070] The present invention provides a preparation method of the focused ultrasound printing ink described in the third aspect in a fourth aspect. The preparation method includes:

[0071] Mix the acrylic monomer and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide to obtain a premixed solution;

[0072] Mix the premixed solution, the initiator, and the nano-hydroxyapatite, and after aging treatment and defoaming, obtain the ink for focused ultrasound printing.

[0073] The aging treatment is to stand at room temperature for more than 7 days and invert and shake several times every day to eliminate sedimentation.

[0074] The defoaming is carried out by centrifugal defoaming;

[0075] After defoaming, it further includes a step of refrigerated storage and is restored to 25 ± 2 °C before use.

[0076] To more clearly illustrate the technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with embodiments. The sources of the various reagents used in the examples and comparative examples of the present invention are not specifically limited and can be directly purchased or synthesized by oneself.

[0077] Example 1

[0078] As Figure 1 shown, a focused ultrasound printing device includes:

[0079] A driving component 1, including a power amplifier 11 and an impedance matcher 12;

[0080] A printing component 2, including a focused transducer 21, a water tank 22, an ink cartridge 23, a deposition plate 24 and a three-dimensional motion mechanism; the focused transducer 21 is located inside the water tank 22; the water tank 22 is located below the ink cartridge 23; the deposition plate 24 is located inside the ink cartridge 23; the three-dimensional motion mechanism includes an X-axis motion mechanism 251, a Y-axis motion mechanism 252 and a Z-axis motion mechanism 253, and the ink cartridge 23 is slidably arranged on the X-axis motion mechanism 251;

[0081] A control component 3, including a control screen 31, a host computer 32 and a slave computer 33.

[0082] Example 2

[0083] As Figure 2 shown, a focused ultrasound printing device includes:

[0084] A driving component 1, including a power amplifier 11 and an impedance matcher 12;

[0085] A printing component 2, including a focused transducer 21, a water tank 22, an ink cartridge 23, a deposition plate 24 and a three-dimensional motion mechanism; the focused transducer 21 is located inside the water tank 22; the water tank 22 is located below the ink cartridge 23; the deposition plate 24 is located inside the ink cartridge 23; the three-dimensional motion mechanism includes an X-axis motion mechanism 251, a Y-axis motion mechanism 252 and a Z-axis motion mechanism 253, and the ink cartridge 23 is fixed by a bracket 26 arranged inside the water tank 22, and the deposition plate 24 is fixed on the Z-axis motion mechanism 253;

[0086] A control component 3, including a control screen 31, a host computer 32 and a slave computer 33.

[0087] Example 3

[0088] Mix methacrylic acid (MAA) and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide (DMAPS) in a molar ratio of 2:1, and magnetically stir at 60 °C until completely dissolved (>2 h) to obtain a premixed solution;

[0089] Add ammonium persulfate (APS) solution (the amount of ammonium persulfate is 0.05 - 0.5 wt% of the total mass of MAA and DMAPS) to the premixed solution, perform ultrasonic dispersion (power: 200 W, time: 15 min), then add nano-hydroxyapatite (particle size: 50 - 100 nm, amount: 70% of the total mass of MAA and DMAPS), and use a planetary stirrer to perform high-speed shear mixing at 2000 rpm for 1 h. Finally, perform aging treatment (stand still at room temperature for ≥7 days, and turn and shake 3 times a day to eliminate sedimentation), centrifugally remove bubbles (use a centrifuge to centrifuge at 3000 rpm for 10 min to remove microbubbles), and store at 4 °C (restore to 25 ± 2 °C before use) to obtain the ink for focused ultrasound printing.

[0090] Example 4

[0091] It is basically the same as Example 1, except that: methacrylic acid (MAA) and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide (DMAPS) are mixed in a molar ratio of 3:1.

[0092] Example 5

[0093] It is basically the same as Example 1, except that: methacrylic acid (MAA) and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide (DMAPS) are mixed in a molar ratio of 4:1.

[0094] Example 6

[0095] It is basically the same as Example 1, except that: methacrylic acid (MAA) and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide (DMAPS) are mixed in a molar ratio of 5:1.

[0096] Example 7

[0097] It is basically the same as Example 1, except that: nano-hydroxyapatite (particle size: 50 - 100 nm, amount: 80% of the total mass of MAA and DMAPS).

[0098] Example 8

[0099] It is basically the same as Example 1, except that: nano-hydroxyapatite (particle size: 50 - 100 nm, amount: 90% of the total mass of MAA and DMAPS).

[0100] Example 9

[0101] It is basically the same as Example 1, except that: nano-hydroxyapatite (particle size is 50 - 100 nm, and the dosage is 100% of the total mass of MAA and DMAPS).

[0102] Comparative Example 1

[0103] It is basically the same as Example 1, except that: methacrylic acid (MAA) and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (DMAPS) are in a ratio of 1:1.5.

[0104] Comparative Example 2

[0105] It is basically the same as Example 1, except that: methacrylic acid (MAA) and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (DMAPS) are in a ratio of 1:2.

[0106] Comparative Example 3

[0107] It is basically the same as Example 1, except that: methacrylic acid (MAA) and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (DMAPS) are in a ratio of 1:3.

[0108] Comparative Example 4

[0109] It is basically the same as Example 1, except that: methacrylic acid (MAA) and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (DMAPS) are in a ratio of 1:4.

[0110] The present invention tested the transmittance-temperature curves of the inks of Examples 3 - 6 and Comparative Examples 1 - 4, and the results are as Figure 3 shown. When the mass ratio of MAA and DMAPS increases from 2:1 to 5:1, the lowest critical solution temperature of the ink rises from 36 °C to 63 °C, which can meet the requirements of focused ultrasound printing. When the mass ratio of MAA and DMAPS increases from 1:4 to 1:1.5, the lowest critical solution temperature of the ink rises from 36 °C to 63 °C, which cannot meet the requirements of focused ultrasound printing.

[0111] Comparative Example 5

[0112] It is basically the same as Example 1, except that: nano-hydroxyapatite is not added.

[0113] The present invention tested the viscosities of the inks of Example 3, Examples 7 - 9 and Comparative Example 5, and the results are as Figure 4As shown, adding nano-hydroxyapatite can regulate the viscosity of the ink to inhibit acoustic streaming disturbance during focused ultrasound printing and improve printing accuracy. As the content of hydroxyapatite in the ink increases, the fluid viscosity shows an increasing trend and exhibits shear thinning at high frequencies, which is beneficial to the polymerization of the ink in the focal area.

[0114] It can be seen from Figure 5 and Figure 6 that the focused ultrasound printing device and ink provided by the present invention can be used to form complex geometric shapes and can be used for Achilles tendon repair and bone tissue repair.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments or equivalently replace some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A focused ultrasound printing device, characterized in that, Comprising: A driving component for providing a stable ultrasonic signal; A printing component including a focusing transducer, a water tank, an ink cartridge, a deposition plate, and a three-dimensional motion mechanism; the focusing transducer is located inside the water tank and is used to receive the ultrasonic signal provided by the driving component and generate a high-precision focused ultrasonic field; the water tank is located below the ink cartridge; the deposition plate is located inside the ink cartridge and is used to deposit a printing target; the three-dimensional motion mechanism is used to control the motion trajectory of the deposition plate; A control component for obtaining parameters of ultrasonic printing and controlling the driving component and the three-dimensional motion mechanism.

2. The focused ultrasound printing device according to claim 1, wherein The driving component includes a power amplifier and an impedance matcher.

3. The focused ultrasound printing device according to claim 1, wherein The control component includes a control screen, a host computer, and a slave computer; The host computer is used to obtain the printing parameters of a printing model and feedback the printing parameters to the slave computer; The slave computer is used to control the power amplifier and the three-dimensional motion mechanism according to the received printing parameters.

4. The focused ultrasound printing device according to claim 1, wherein, The three-dimensional motion mechanism includes an X-axis motion mechanism, a Y-axis motion mechanism, and a Z-axis motion mechanism.

5. The focused ultrasound printing device according to claim 4, characterized in that, The ink cartridge is slidably arranged on the X-axis motion mechanism; or The ink cartridge is fixed by a bracket arranged inside the water tank, and the deposition plate is fixed on the Z-axis motion mechanism.

6. A focused ultrasound printing method, characterized in that, Implemented by the device according to any one of claims 1-5, the printing method includes: Constructing a printing model; Performing model slicing and determining the parameters of focused ultrasonic printing; the parameters include the scanning path of the focusing focus, the scanning speed, the filling density, and the sound pressure amplitude; Performing focused ultrasonic printing with ink.

7. The focused ultrasound printing method according to claim 6, wherein During the focused ultrasonic printing process, the scanning speed of the focusing focus is 0.4-8 mm / s, the filling density is 30-100%, and the sound pressure amplitude is 20-100 MPa.

8. A focused ultrasound printing ink, characterized in that, The device according to any one of claims 1-5 can realize the forming of complex geometric structures, and the ink includes a polymer monomer, an initiator, and nano-hydroxyapatite; The polymer monomer includes an acrylic monomer and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide; the molar ratio of the acrylic monomer to [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide is 1-5:1; The dosage of the nano-hydroxyapatite is not less than 30% of the mass of the polymer monomer.

9. The focused ultrasound printing ink according to claim 8, characterized in that, The dosage of the nano-hydroxyapatite is 30-100% of the mass of the polymer monomer; and / or The dosage of the initiator is 0.05-0.5% of the mass of the polymer monomer; the initiator is preferably a radical initiator, more preferably ammonium persulfate.

10. A method for preparing the focused ultrasound printing ink according to claim 8 or 9, characterized in that, The preparation method includes: Mixing the acrylic monomer and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide to obtain a premixed solution; Mixing the premixed solution, the initiator, and the nano-hydroxyapatite, and performing aging treatment and degassing to obtain the ink for focused ultrasonic printing.

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