Ultrasonic Additive Manufacturing Device and Method

Abstract

The invention discloses an ultrasonic additive manufacturing method, comprising the steps of analyzing and slicing a target model, controlling a liquid level, and ultrasonic printing; the invention discloses an ultrasonic additive manufacturing device, comprising a bracket and an ultrasonic printing head installed inside the bracket, a material cylinder, a two-dimensional motion module, and a vertical motion module. The invention controls the ultrasonic advance direction and range and the sound velocity cone diameter through a transducer and an ultrasonic wave lead-out device of the ultrasonic additive manufacturing device. The ultrasonically curable material in the material cylinder is cured at the focus of the ultrasonic beam, thereby performing ultrasonic printing, achieving the additive manufacturing effect, while having a simple device structure and lower ultrasonic printing cost.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and particularly to an ultrasonic additive manufacturing device and method. Background Art

[0002] Additive manufacturing technology, also known as 3D printing, is a kind of rapid prototyping technology, which integrates computer-aided design, material processing and forming technology. Based on digital model files, special metal materials, non-metal materials and medical biological materials are stacked layer by layer in ways such as extrusion, sintering, melting, photocuring, spraying, etc. to manufacture solid objects. Due to its characteristics such as fast forming speed, simple forming process and raw material saving, additive manufacturing technology has been widely studied and applied in various fields.

[0003] Currently, the additive manufacturing technologies for resin materials include: SLA, SLS, PolyJet, DLP, FDM, etc. These technologies have some problems:

[0004] (1) High-precision devices such as SLA, SLS, PolyJet, etc. have high costs, require expensive accessories such as lasers, or have high processing requirements for nozzles, and have high requirements for the storage and use environment of the devices;

[0005] (2) FDM has low precision, the heating source is exposed, which is likely to cause safety hazards.

[0006] In additive manufacturing, ultrasonic waves are often used as an auxiliary means to detect or adjust the internal structure of products. Its main curing means is still photocuring and thermal curing, which can be regarded as adding a device that generates ultrasonic waves to a conventional 3D printing device. Currently, there are materials that can be cured by ultrasonic waves. For example, in the patent document "Ultrasonic Curing Dental Filling Materials" with the patent number CN200580014019.0, it is mentioned that the martensitic transformation of the filler component is induced by using ultrasonic waves or chemical initiators. The patent application with the application number CN90105864.5 for a kind of ultrasonic-cured dental restorative resin also cures the resin by ultrasonic waves. An article "Ultrasonic Acceleration of Epoxy Resin Curing" was published in the journal "Petroleum Engineering Construction". From the above materials, it can be seen that it is feasible to apply ultrasonic waves to the curing means of additive manufacturing, but the current additive manufacturing technology and corresponding equipment are not suitable for ultrasonic additive manufacturing (i.e., ultrasonic printing).

[0007] To solve the above problems, the present invention proposes an ultrasonic additive manufacturing device and method with low cost, safety, environmental protection, high efficiency and precision. Summary of the Invention

[0008] To solve the technical problems of high processing requirements and high costs existing in the current additive manufacturing field, the present invention provides such an ultrasonic additive manufacturing device, including:

[0009] The bracket provides support for the entire device and bears various parts and components.

[0010] The material cylinder is fixed on the bracket, and a printing substrate that moves vertically up and down is arranged inside the material cylinder.

[0011] The ultrasonic printing head is located above the material cylinder and performs two-dimensional movement in the horizontal plane. The ultrasonic printing head includes a fixed part, a transducer, and an ultrasonic guiding device arranged from top to bottom. The bottom end of the ultrasonic guiding device is conical, and a through hole, namely an ultrasonic conduction hole, is provided at the center. The bottom of the through hole has a rounded corner, which can control the advancing direction and range of ultrasonic waves. The transducer controls the diameter of the sound velocity cone surface of the ultrasonic waves. This sound velocity cone surface diameter is the single-track line width that can be executed by ultrasonic printing. A suitable transducer is selected according to the single-track line width before printing starts.

[0012] The ultrasonic generator is located outside the bracket and is electrically connected to the transducer through a circuit passing through the fixed part.

[0013] The vertical movement module is installed on the bracket and drives the printing substrate to move vertically up and down in the material cylinder.

[0014] The two-dimensional movement module is installed on the bracket and drives the ultrasonic printing head to perform two-dimensional movement in the horizontal plane above the material cylinder.

[0015] Furthermore, the two-dimensional movement module is installed on the top layer of the bracket. The two-dimensional movement module includes a horizontal movement module and a vertical movement module. The vertical movement module can adopt a lead screw transmission structure or a belt transmission structure, and the horizontal movement module can adopt a lead screw transmission structure or a gear transmission structure.

[0016] Further, the vertical motion module is fixed between the base and the top layer of the bracket. The longitudinal motion module adopts a belt drive structure, including a left motor, a right motor, a transmission rod, and a transmission belt. The left motor and the right motor are respectively arranged on the two side edges of the bracket. The two ends above the transmission rod are slidably connected to the guide rails on the edges of the top layer of the bracket. Two first guide wheels are arranged at the two ends below the transmission rod. Second guide wheels are respectively arranged on the other two side edges of the bracket. The transmission belt connects the left motor, the first guide wheels, the second guide wheels, and the right motor into a whole. The left motor and the right motor move in opposite directions. The transmission rod is driven by the transmission belt to move longitudinally on the top layer of the bracket. When the output end of the left motor rotates counterclockwise and the right motor rotates clockwise, at this time, the outer transmission belts all move towards the left motor and the right motor, and the inner transmission belts all move away from the left motor and the right motor. Since the total length of the transmission belt remains unchanged, under the action of the first guide wheels and the second guide wheels, the transmission rod slides along the guide rail on the edge of the top layer of the bracket away from the left motor and the right motor. Similarly, when the output end of the left motor rotates clockwise and the right motor rotates counterclockwise, the transmission rod slides along the guide rail on the edge of the top layer of the bracket towards the left motor and the right motor.

[0017] The transverse motion module adopts a ball screw drive structure, including a base, a horizontal axis motor, and a ball screw connected to the horizontal axis motor. The base is connected to the fixing part of the ultrasonic print head. A guide rail is arranged above the transmission rod. The output end of the horizontal axis motor is connected to the screw of the ball screw. The transmission rod of the ball screw is connected to the base through a nut. The rotation of the output end of the horizontal axis motor is converted into the ultrasonic print head moving linearly along the transmission rod. Under the combined action of the transverse motion module and the longitudinal motion module, the ultrasonic print head can move to any position in the transverse (X-axis) and longitudinal (Y-axis) directions.

[0018] Further, the vertical motion module includes a vertical axis motor, a ball screw, an auxiliary rod, and a slider. The vertical axis motor is installed on an edge of the top layer of the bracket. One end of the ball screw is connected to the output end of the vertical axis motor, and the other end is connected to the base of the bracket. The auxiliary rod is located between the top layer and the base of the bracket on both sides of the screw of the ball screw. The screw of the ball screw is driven by the vertical axis motor. The slider is connected to the nut of the ball screw. One end of the printing substrate is connected to the slider and sleeved on the auxiliary rod. The rotational motion of the screw is converted into the linear motion of the slider, thereby driving the printing substrate to move linearly. Therefore, when the vertical axis motor operates, it drives the printing substrate to move up and down vertically.

[0019] Further, the printing substrate is of a stepped structure. The upper end of the printing substrate is a connecting part and is connected to the vertical motion module. The lower part of the printing substrate is a working platform. The connecting part and the working platform are connected by a connecting rod. A plurality of through holes are arranged in the working platform. When the working platform is immersed in the material cylinder, during the ultrasonic printing process, the liquid printing material can continuously flow into the working platform from the through holes, so that the liquid printing material in the working platform is always evenly distributed.

[0020] Furthermore, the material cylinder is communicated with an external liquid storage cylinder through a liquid extraction pump. An infrared detector is arranged at the edge of the mouth of the material cylinder. The infrared detector is electrically connected to the liquid extraction pump through a control module. The orientation of the infrared detector is perpendicular to the liquid level. When the liquid level in the material cylinder drops, the infrared detector feeds back the information of the liquid level drop to the liquid extraction pump, and the liquid extraction pump starts and pumps the material liquid in the liquid storage cylinder into the material cylinder.

[0021] An ultrasonic additive manufacturing method, which performs ultrasonic printing in the ultrasonic additive manufacturing device, includes the following steps:

[0022] a. Analyze the target model parameters and layer them to determine the parameters for printing each layer of the target model;

[0023] b. Add the liquid printing material into the material cylinder until the initial liquid level height in the material cylinder is reached, and immerse the printing substrate into the liquid printing material in the material cylinder.

[0024] c. The two-dimensional motion module drives the ultrasonic printing head to perform two-dimensional motion in the horizontal and vertical directions to reach the printing starting point of this layer of the target model according to the parameters required for printing each layer of the target model. The vertical motion module drives the working platform to move vertically so that the printing substrate is located below the initial liquid level in the material cylinder.

[0025] d. Start the ultrasonic generator connected to the ultrasonic printing head. The liquid printing material directly below the transducer is cured and deposited on the printing substrate under the action of ultrasonic waves. According to the parameters for printing this layer, the two-dimensional motion module drives the ultrasonic printing head to perform ultrasonic printing while moving horizontally. After depositing one layer, the vertical motion module drives the working platform to descend by a set height, and then ultrasonic printing is performed again.

[0026] e. During the ultrasonic printing process, always keep the liquid level in the material cylinder at the initial liquid level height.

[0027] f. Repeat steps c - e until the target model is formed into a finished product with a three-dimensional entity.

[0028] Furthermore, in step b, add the liquid printing material into the material cylinder and the liquid storage cylinder, and start the infrared detector to detect the liquid level height of the liquid printing material in the material cylinder. When the infrared detector detects that the liquid level in the material cylinder is low, the liquid extraction pump starts and pumps the liquid printing material in the liquid storage cylinder into the material cylinder until the initial liquid level height in the material cylinder is reached, and the working platform is immersed in the liquid printing material in the material cylinder.

[0029] Further, in step e, during the ultrasonic printing process, the liquid printing material is cured, resulting in a reduction in the volume of the liquid. When the infrared detector detects that the liquid level in the material cylinder is different from the initial liquid level, the liquid pumping pump is started, and the liquid printing material is pumped from the liquid storage cylinder to the material cylinder. After the liquid level in the material cylinder reaches the initial liquid level, the liquid pumping pump stops pumping.

[0030] Further, the initial liquid level in the material cylinder is the ultrasonic focal plane of the ultrasonic printing head. The transducer controls the generation of an ultrasonic beam, and the ultrasonic output device outputs the ultrasonic beam. The plane where the focus of the ultrasonic beam is located (i.e., the ultrasonic focal plane) coincides with the initial liquid level of the material cylinder. The energy of the ultrasonic beam is concentrated at a point on this plane. Therefore, the liquid surface below the transducer is cured at the ultrasonic focus.

[0031] Further, the liquid printing material is a material that can be cured by ultrasonic waves.

[0032] Further, the liquid printing material is a liquid resin material that can be cured by ultrasonic waves.

[0033] Advantageous Effects

[0034] In the present invention, an ultrasonic additive manufacturing device combines ultrasonic waves with 3D printing technology, using ultrasonic waves as the means for curing the material. The principle is that the power supply outputs to the ultrasonic generator. The function of the ultrasonic generator is to convert the commercial power into a high-frequency alternating current signal that matches the ultrasonic transducer and drive the ultrasonic transducer to work. The function of the transducer is to convert high-frequency electrical energy into mechanical energy, that is, ultrasonic waves, and then the ultrasonic output device outputs the ultrasonic waves. By controlling the diameter of the sound velocity cone surface via the transducer and controlling the advancing direction and range of the ultrasonic waves via the ultrasonic output device, the material in the material cylinder that can be cured by ultrasonic waves is cured at the focal plane of the ultrasonic beam. By controlling the movement of the ultrasonic printing head through the two-dimensional motion module according to the parameters of the target model, while ensuring that the height of the ultrasonic focal plane of the ultrasonic printing head and the liquid level height in the material cylinder remain consistent, ultrasonic printing is thus carried out. While achieving the additive manufacturing effect, the device has a simple structure and lower ultrasonic printing costs. Brief Description of the Drawings

[0035] Figure 1 It is a schematic structural diagram of the ultrasonic additive manufacturing device of the present invention from one angle.

[0036] Figure 2 It is a schematic structural diagram of the ultrasonic additive manufacturing device of the present invention from another angle.

[0037] Figure 3 It is a schematic diagram of the printing substrate of the ultrasonic additive manufacturing device of the present invention.

[0038] Figure 4Schematic diagram of the ultrasonic print head of the ultrasonic additive manufacturing equipment of the present invention.

[0039] Figure 5 Schematic diagram of the longitudinal motion module of the ultrasonic additive manufacturing equipment of the present invention.

[0040] Figure 6 Schematic diagram of the vertical motion module of the ultrasonic additive manufacturing equipment of the present invention.

[0041] Figure 7 Schematic diagram of the lateral motion module of the ultrasonic additive manufacturing equipment of the present invention.

[0042] Figure 8 Schematic diagram of the process flow of the ultrasonic additive manufacturing method of the present invention.

[0043] The reference signs in the drawings are: 1 - bracket, 2 - lateral motion module, 3 - longitudinal motion module, 4 - vertical motion module, 5 - ultrasonic print head, 6 - material cylinder, 7 - printing substrate, 8 - left motor, 9 - right motor, 10 - auxiliary rod, 11 - liquid storage cylinder, 12 - liquid pumping pump, 13 - infrared detector, 14 - working platform, 15 - connecting part, 16 - transducer, 17 - ultrasonic wave guiding device, 18 - fixing part, 19 - first guide wheel, 20 - second guide wheel, 21 - transmission rod, 22 - transmission belt, 23 - vertical shaft motor, 24 - horizontal shaft motor, 25 - ultrasonic wave generator. Detailed implementation manners

[0044] The following further describes the present invention in conjunction with the Figure 1-8 accompanying drawings and embodiments.

[0045] An ultrasonic additive manufacturing equipment, including a bracket 1 and a printing component installed inside the bracket 1, wherein:

[0046] The bracket 1 includes a bracket 1 base, side edges provided on the bracket 1 base, and a top layer provided above the side edges;

[0047] The material cylinder 6 is provided on the bracket 1 base;

[0048] The printing substrate 7 is located inside the material cylinder 6. One end of the printing substrate 7 is connected to the vertical motion module 4 and is driven by the vertical motion module 4 to move up and down. The vertical motion module 4 is fixed between the bracket 1 base and the top layer. The printing substrate 7 is of a stepped structure. The upper end of the printing substrate 7 is a connecting part 15 and is connected to the lifting motion module. Below the printing substrate 7 is a working platform 14. The connecting part 15 and the working platform 14 are connected by a connecting rod;

[0049] The ultrasonic print head 5 includes a fixing portion 18, a transducer 16 and an ultrasonic wave guide device connected in sequence from top to bottom. The external ultrasonic generator passes through the fixing portion and is electrically connected to the transducer. The ultrasonic print head 5 is located above the printing substrate 7. The fixing portion 18 is connected to a two-dimensional motion module and the ultrasonic print head 5 is driven by the two-dimensional motion module to move on a horizontal plane. The two-dimensional motion module is connected to the top layer of the bracket 1. The ultrasonic generator 25 and the transducer 16 are used together to generate continuous and stable ultrasonic waves. The ultrasonic wave export device 17 outputs the ultrasonic wave, wherein the transducer 16 controls the sound velocity cone diameter of the ultrasonic wave, and the ultrasonic wave export device 17 controls the direction and range of the ultrasonic wave. The sound velocity cone diameter is the single-channel line width executable by ultrasonic printing. Before printing starts, a suitable transducer 16 is selected according to the single-channel line width.

[0050] The two-dimensional motion module includes a lateral motion module 2 and a longitudinal motion module 3. The lateral motion module 22 can adopt a screw transmission structure or a transmission belt 22 transmission structure, and the longitudinal motion module 3 can adopt a screw transmission structure or a gear transmission structure.

[0051] The vertical motion module includes a vertical axis motor 23, a ball screw, an auxiliary rod 10 and a slider. The vertical axis motor 23 is installed on an edge of the top layer of the bracket 1. One end of the ball screw is connected to the output end of the vertical axis motor 23, and the other end is connected to the base of the bracket 1. The auxiliary rod 10 is located between the top layer of the bracket 1 and the base of the bracket 1, and is located on both sides of the screw of the ball screw. The screw of the ball screw is driven by the vertical axis motor 23. The slider is connected to the nut of the ball screw. One end of the printing substrate 7 is connected to the slider and inserted into the auxiliary rod 10. The rotational motion of the screw is converted into the linear motion of the slider, thereby driving the printing substrate 7 to move linearly. Therefore, when the vertical axis motor 23 is running, it drives the printing substrate 7 to move up and down in the vertical direction.

[0052] Example 1

[0053] The longitudinal motion module 3 adopts a belt transmission structure, and the transverse motion module 2 adopts a screw transmission structure.

[0054] The longitudinal motion module 3 includes a left motor 8, a right motor 9, a transmission rod 21 and a transmission belt 22. The left motor 8 and the right motor 9 are respectively arranged on the edges of both sides of the bracket 1. The two ends above the transmission rod 21 are slidably connected with the edges of the top layer of the bracket 1. The two ends below the transmission rod 21 are both provided with a first guide wheel 19. The second guide wheels 20 are respectively provided on the other two side edges of the bracket 1. The transmission belt 22 connects the left motor 8, the first guide wheel 19, the second guide wheel 20 and the right motor 9 as a whole. The left motor 8 and the right motor 9 make opposite-direction movements, and the transmission rod 21 is driven to make longitudinal movements on the top layer of the bracket 1 through the transmission belt 22.

[0055] The lateral motion module 2 includes a horizontal axis motor 24, a ball screw, and a base. The horizontal axis motor 24 and the ball screw are arranged on the transmission rod 21. The output end of the horizontal axis motor 24 drives the screw of the ball screw to rotate. The nut of the ball screw is connected to the base. The rotational motion of the screw is converted into the linear motion of the slider, thereby driving the ultrasonic print head 5 to perform linear motion.

[0056] Embodiment 2

[0057] The longitudinal motion module adopts a lead screw drive structure, and the lateral motion module adopts a gear drive structure. (Not shown in the drawings).

[0058] The longitudinal motion module includes a longitudinal motor, a ball screw, and a longitudinal rod. The two ends above the longitudinal rod are slidably connected to the edges of the top layer of the bracket. The output end of the longitudinal motor drives the screw of the ball screw to rotate. The nut of the ball screw is connected to one end of the longitudinal rod. The rotational motion of the screw is converted into the linear motion of the nut, thereby driving the longitudinal rod to perform linear motion.

[0059] The lateral motion module includes a base and a horizontal axis motor arranged on the base. The base is connected to the ultrasonic print head. A guide rail is arranged above the longitudinal rod. The output end of the horizontal axis motor is docked with the guide rail. The rotation of the output end of the horizontal axis motor is converted into the lateral linear motion of the ultrasonic print head along the transmission.

[0060] Using the ultrasonic additive manufacturing equipment of Embodiment 1 for ultrasonic printing, the steps are as follows:

[0061] a. Analyze the target model through software such as Cura and 3DPrinterOS and slice the target model to obtain the image data required for each layer of the target model. Input the image data into the control module of the ultrasonic additive manufacturing equipment;

[0062] b. Add the liquid printing material to the material cylinder 6 and the liquid storage cylinder 11, and start the infrared detector 13 to detect the liquid level height of the liquid printing material in the material cylinder 6. When the infrared detector 13 detects that the liquid level in the material cylinder 6 is low, the liquid pumping pump 12 is started to pump the liquid printing material in the liquid storage cylinder 11 into the material cylinder 6 until the initial liquid level height in the material cylinder 6, and the working platform 14 is immersed in the liquid printing material in the material cylinder 6;

[0063] c. The lateral motion module 2 of the two-dimensional motion module is connected to the fixing part 18 of the ultrasonic print head 5. Therefore, the lateral motion module 22 can drive the ultrasonic print head 5 to move left and right horizontally. The lateral motion module 2 is connected to the transmission rod 21 of the longitudinal motion module 3 and moves on the guide rail above the transmission rod 21;

[0064] When the left motor 8 and the right motor 9 of the longitudinal motion module 3 rotate in opposite directions, under the action of the first guide pulley 19 and the second guide pulley 20, the transmission belt 22 can drive the transmission rod 21 to move longitudinally back and forth, thereby driving the transverse motion module 2 to move back and forth. Under the combined action of the transverse motion module 2 and the longitudinal motion module 3, the ultrasonic print head 5 can move to any point in the transverse (X-axis) and longitudinal (Y-axis) directions;

[0065] The two-dimensional motion module drives the ultrasonic print head 5 to perform two-dimensional motion in the transverse and longitudinal directions according to the image data required to be printed for each layer of the target model. The vertical motion module 4 drives the working platform 14 to move up and down along the auxiliary rod 10, so that the height difference between the working platform 14 and the liquid surface under the liquid surface is the same as the thickness of each layer of the target model in the image data;

[0066] d. Start the ultrasonic generator 25 connected to the ultrasonic print head 5. The liquid printing material directly below the transducer 16 is cured and deposited on the working platform 14 under the action of ultrasonic waves. During the deposition process, the liquid printing material continuously penetrates into the working platform 14 from the through holes of the working platform 14. After one layer is deposited, the vertical motion module 4 drives the working platform 14 to descend by the height of one layer thickness of the image data, and then ultrasonic printing is performed again;

[0067] e. During the ultrasonic printing process, when the infrared detector 13 detects that the liquid level in the material cylinder 6 is different from the initial liquid level, the liquid pumping pump 12 is started to pump the liquid printing material from the liquid storage cylinder 11 to the material cylinder 6. After the liquid level in the material cylinder 6 reaches the initial liquid level, the liquid pumping pump 12 stops pumping;

[0068] f. Repeat steps c - e until the target model is formed into a finished product with a three-dimensional entity.

[0069] The basic components of the liquid printing material can be one or more compounds such as methyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, and triethylene glycol dimethacrylate.

[0070] The above embodiments only represent the preferred embodiments of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations, improvements, and substitutions can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. An ultrasonic additive manufacturing method, characterized in that: Ultrasonic printing is performed inside an ultrasonic additive manufacturing device, and the ultrasonic additive manufacturing device includes: a bracket (1); a material cylinder (6) fixed on the bracket (1), and a vertically lifting printing substrate (7) is arranged inside the material cylinder (6); an ultrasonic printing head (5) located above the material cylinder (6), and the ultrasonic printing head (5) includes a fixing part (18), a transducer (16) and an ultrasonic guiding device (17) arranged from top to bottom. An ultrasonic conduction hole is provided at the bottom end of the ultrasonic guiding device (17); an ultrasonic generator (25) electrically connected to the transducer (16); a vertical motion module installed on the bracket (1) to drive the printing substrate (7) to move up and down in the material cylinder (6). The printing substrate (7) has a stepped structure. The upper end of the printing substrate (7) is a connecting part (15) and is connected to the vertical motion module. Below the printing substrate (7) is a working platform (14), and the connecting part (15) and the working platform (14) are connected by a connecting rod; a two-dimensional motion module installed on the bracket (1) to drive the ultrasonic printing head (5) to perform two-dimensional lateral and longitudinal motions in the plane above the material cylinder (6); The transducer (16) controls the diameter of the sound velocity cone surface of the ultrasonic wave, and the ultrasonic guiding device (17) controls the advancing direction and range of the ultrasonic wave. The diameter of this sound velocity cone surface is the single-track line width that can be executed by ultrasonic printing. A suitable transducer (16) is selected according to the single-track line width before printing starts; During operation, the vertical motion module (4) drives the working platform (14) to move vertically so that the working platform (14) is located below the initial liquid level in the material cylinder. The liquid printing material is a liquid resin material that can be cured by ultrasonic waves. The material in the material cylinder that can be cured by ultrasonic waves is cured at the focal plane of the ultrasonic beam; the ultrasonic generator connected to the ultrasonic printing head is started, and the liquid printing material directly below the transducer is cured and deposited on the printing substrate under the action of the ultrasonic wave; The method includes the following steps: a. Analyze the target model parameters and layer them to determine the printing parameters for each layer of the target model; b. Add the liquid printing material into the material cylinder (6) until it reaches the initial liquid level height in the material cylinder (6), and the printing substrate (7) is immersed in the liquid printing material in the material cylinder (6); c. The two-dimensional motion module drives the ultrasonic printing head (5) to perform two-dimensional lateral and longitudinal motions to reach the printing starting point of this layer of the target model according to the printing parameters required for each layer of the target model. The vertical motion module drives the working platform (14) to move up and down so that the printing substrate (7) is located below the initial liquid level in the material cylinder (6); d. Start the ultrasonic generator (25) connected to the ultrasonic printing head (5). The liquid printing material directly below the transducer (16) is cured and deposited on the printing substrate (7) under the action of the ultrasonic wave. According to the printing parameters of this layer, the two-dimensional motion module drives the ultrasonic printing head (5) to perform ultrasonic printing while moving horizontally. After depositing one layer, the vertical motion module drives the working platform (14) to descend by a set height, and then ultrasonic printing is performed again; e. During the ultrasonic printing process, always keep the liquid level in the material cylinder (6) at the initial liquid level height; f. Repeat steps c - e until the target model is formed into a finished product with a three - dimensional entity. The basic components of the liquid printing material are one or more compounds selected from methyl acrylate, methyl methacrylate, 2 - hydroxyethyl methacrylate, and triethylene glycol dimethacrylate.

2. The ultrasonic additive manufacturing method according to claim 1, wherein: In step b, add the liquid printing material to the material cylinder (6) and the liquid storage cylinder (11), and start the infrared detector (13) to detect the liquid level height of the liquid printing material in the material cylinder (6). When the infrared detector (13) detects that the liquid level in the material cylinder (6) is low, the liquid extraction pump (12) starts to pump the liquid printing material in the liquid storage cylinder (11) into the material cylinder (6) until the initial liquid level height in the material cylinder (6) is reached, and the working platform (14) is immersed in the liquid printing material in the material cylinder (6).

3. The ultrasonic additive manufacturing method according to claim 2, wherein: In step e, during the ultrasonic printing process, when the infrared detector (13) detects that the liquid level height in the material cylinder (6) is different from the initial liquid level, the liquid extraction pump (12) starts to pump the liquid printing material from the liquid storage cylinder (11) into the material cylinder (6). After the liquid level in the material cylinder (6) reaches the initial liquid level, the liquid extraction pump (12) stops pumping.

4. The ultrasonic additive manufacturing method according to any one of claims 1-3, characterized in that: The initial liquid level in the material cylinder (6) is the ultrasonic focal plane of the ultrasonic printing head (5).

5. The ultrasonic additive manufacturing method according to claim 4, wherein: In step c, the height by which the working platform (14) descends is the same as the thickness of each layer of the target model.

6. The ultrasonic additive manufacturing method according to claim 5, wherein: The parameters for printing each layer of the target model include at least the shape, length, width, and height of each layer of the target model.

7. The ultrasonic additive manufacturing method according to claim 6, wherein: The liquid printing material is a material that can be formed by ultrasonic curing.

8. The ultrasonic additive manufacturing method according to claim 7, characterized in that: The liquid printing material is a liquid resin material that can be formed by ultrasonic curing.

9. The ultrasonic additive manufacturing method according to claim 1, wherein: The two - dimensional motion module is installed on the top layer of the bracket (1). The two - dimensional motion module includes a transverse motion module (2) and a longitudinal motion module (3). The transverse motion module (2) is arranged on the longitudinal motion module (3) and moves horizontally in the transverse direction along the longitudinal motion module (3). The longitudinal motion module (3) is arranged on the top layer of the bracket (1) and moves horizontally in the longitudinal direction along the edges on both sides of the top layer.

10. The ultrasonic additive manufacturing method according to claim 9, wherein: The vertical motion module (4) is fixed between the base and the top layer of the bracket (1). The longitudinal motion module (3) can adopt a lead screw drive structure or a belt drive structure, and the transverse motion module (2) can adopt a lead screw drive structure or a gear drive structure.

11. The ultrasonic additive manufacturing method according to claim 10, wherein: The longitudinal motion module (3) adopts a belt drive structure, including a left motor (8), a right motor (9), a transmission rod (21) and a transmission belt (22). The left motor (8) and the right motor (9) are respectively arranged on the two side edges of the bracket (1). The two ends above the transmission rod (21) are slidably connected to the edges of the top layer of the bracket (1). The two ends below the transmission rod (21) are both provided with first guide wheels (19). Second guide wheels (20) are respectively arranged on the other two side edges of the bracket (1) opposite to the left motor (8) and the right motor (9). The transmission belt (22) connects the left motor (8), the first guide wheel (19), the second guide wheel (20) and the right motor (9) into a whole. The left motor (8) and the right motor (9) move in opposite directions, and drive the transmission rod (21) to make a longitudinal motion on the top layer of the bracket (1) through the transmission belt (22).

12. The ultrasonic additive manufacturing method according to claim 11, wherein: The transverse motion module (2) adopts a lead screw drive structure, including a base, a horizontal axis motor (24) and a ball screw connected to the horizontal axis motor (24). The base is connected to the fixing part (18) of the ultrasonic print head (5). A guide rail is arranged above the transmission rod (21). The output end of the horizontal axis motor (24) is connected to the screw rod of the lead screw. The transmission rod (21) of the lead screw is connected to the base through a nut. The rotation of the output end of the horizontal axis motor (24) is converted into a transverse linear motion of the ultrasonic print head (5) along the transmission rod (21).

13. The ultrasonic additive manufacturing method according to claim 12, characterized in that: The vertical motion module includes a vertical axis motor (23), a ball screw, an auxiliary rod (10) and a slider. The vertical axis motor (23) is installed on an edge of the top layer of the bracket (1). One end of the ball screw is connected to the output end of the vertical axis motor (23), and the other end is connected to the base of the bracket (1). The auxiliary rod (10) is located between the top layer of the bracket (1) and the base of the bracket (1) on both sides of the screw rod of the ball screw. The screw rod of the ball screw is driven by the vertical axis motor (23). The slider is connected to the nut of the ball screw. One end of the printing substrate (7) is connected to the slider and sleeved on the auxiliary rod (10).

14. The ultrasonic additive manufacturing method according to claim 7, wherein: A plurality of through holes are arranged in the working platform (14).

15. The ultrasonic additive manufacturing method according to claim 8, characterized in that: The material cylinder (6) is communicated with an external liquid storage cylinder (11) through a liquid extraction pump (12).

16. The ultrasonic additive manufacturing method according to claim 9, wherein: An infrared detector (13) is arranged at the edge of the opening of the material cylinder (6). The orientation of the infrared detector (13) is perpendicular to the liquid level. The infrared detector (13) is communicatively connected to an external controller. The infrared detector (13) transmits the detection data to the controller, and the controller controls the opening or closing of the liquid extraction pump (12) according to the detection data, so as to control the liquid level height in the material cylinder (6).

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