Ultrasonic 3D printing device and method

Abstract

Embodiments of the present application provide an ultrasonic 3D printing device and method. The ultrasonic 3D printing device comprises: a forming chamber (1), a forming module, an emission module, a motion module, an auxiliary functional module, and a central power supply (17); the forming module is arranged in the forming chamber (1) and comprises a bio‑ink cartridge (2) and bio-ink (3); the emission module comprises a focused ultrasonic transducer array (4), which is mounted on a sliding block (6) of a three-dimensional motion guide rail in the motion module by means of a connecting member; the motion module comprises a guide rail having a three-dimensional motion bearing function, and a displacement control unit (10); the auxiliary functional module comprises a high-definition camera (11), a high-definition display screen (12), a sterilization device (13) and a temperature control device (15); and the central power supply (17) is used for providing electric power required by the ultrasonic 3D printing device. The ultrasonic 3D printing device of the present invention improves the precision and biosafety of ultrasonic biological 3D printing.

Description

An ultrasonic 3D printing device and printing method TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of biological 3D printing technology, and in particular to an ultrasonic 3D printing device and printing method. BACKGROUND

[0002] 3D printing technology is currently one of many rapid prototyping technologies, also known as additive manufacturing, which is an advanced technology that uses metal powder, plastic or high molecular solution and other materials to construct objects through layer-by-layer printing based on digital model files. At present, a part of biological implants are constructed by 3D printing technology. However, the existing biological 3D printing technology generally constructs the required biological materials by using inkjet, laser direct writing, extrusion, light curing and other 3D printing methods in vitro. The following problems may occur during implantation: (1) soft biological materials such as hydrogel may be artificially damaged; (2) a large range of open surgery is performed, increasing the risk of infection; (3) the interface between the biological material and the tissue does not match, reducing its biological function.

[0003] The leading biological 3D printing technology tends to construct bioactive materials / devices directly in vivo. Near-infrared light (NIR) as an effective stimulation and regulation medium has been reported to be used for non-invasive in vivo 3D biological printing of tissue structure. However, since NIR can only penetrate biological tissues with a depth of less than 5 mm, it is still challenging to use NIR to penetrate optical scattering media (such as biological tissues) and perform subsequent 3D printing operations. In addition, the light attenuation of the photosensitive ink itself, the biological toxicity of the photoinitiator, and other factors limit the material selection and construction size of the light-cured biological 3D printing.

[0004] Ultrasound has stronger penetration performance, which can reach centimeter level, sufficient to penetrate various tissues in vivo. At the same time, ultrasound can also be focused by a focused ultrasound (FUS) transducer in a certain "focus point", which can effectively avoid energy absorption of tissues in non-target areas and protect healthy tissues outside the implanted material. In addition, since the FUS transducer can generate positive and negative pressure sound waves with a frequency of megahertz alternating and propagating along the depth direction, the technology can continuously and accurately deliver acoustic energy to the focal region. However, the current focused ultrasound biological 3D printing device still has problems such as low precision (millimeter level), high acoustic pressure (peak value reaching more than 35 MPa), single function and complex device, and there is still a distance for realizing high-precision ultrasonic biological 3D printing, tissue repair and other clinical applications.

[0005] SUMMARY

[0006] Therefore, the embodiments of the present application provide an ultrasonic 3D printing device and printing method to solve the above problems.

[0007] The application provides an ultrasonic 3D printing device, which comprises a forming cabin (1), a forming module, an emission module, a motion module, an auxiliary function module and a central power supply (17); the forming module is arranged in the forming cabin (1) and comprises a biological ink container (2) and biological ink (3); the biological ink container (2) is used for containing the biological ink (3) and printing initial products; the biological ink (3) is based on ultrasonic action to realize thermal curing; the emission module comprises a focused ultrasonic transducer group (4) which is used for accurately curing and printing biological ink at different spatial positions and is installed on a slider (6) of a three-dimensional motion guide rail in the motion module through a connecting piece; the motion module comprises a guide rail with a three-dimensional motion function and a displacement control unit (10); the displacement control unit (10) cuts a preset three-dimensional model to output path instructions, controls the slider (6) installed on the guide rail to displace and drives the focused ultrasonic transducer (4) to accurately cure biological ink at spatial positions; the auxiliary function module comprises a high-definition camera (11), a high-definition display screen (12), a sterilization device (13) and a temperature control device (15); the high-definition camera (11) records a scene in a focused ultrasonic printing range in real time and transmits a picture to the connected high-definition display screen (12) to feed back a real-time printing state for adjusting printing parameters; the sterilization device (13) is used for killing microorganisms in a printing environment; the temperature control device (15) is used for maintaining the constancy of temperature in the printing environment; and the central power supply (17) is used for providing power required by the ultrasonic 3D printing device.

[0008] In another implementation manner of the application, the focused ultrasonic transducer group (4) is integrated with focused ultrasonic transducers of different frequencies.

[0009] In another implementation manner of the application, the focused ultrasonic transducer group (4) is regulated by a focused ultrasonic control unit (5) and is used for generating ultrasonic focusing effects with different power densities.

[0010] In another implementation manner of the application, the frequency range of the focused ultrasonic transducer group (4) is 20 kHz-50 MHz.

[0011] In another implementation manner of the application, the guide rail with a three-dimensional motion function comprises an x-axis screw guide rail (7), a y-axis screw guide rail (8) and a z-axis screw guide rail (9); and the displacement of the slider (6) in the x, y and z axis directions drives the focused ultrasonic transducer group (4) to focus and print biological ink at different spatial positions.

[0012] In another implementation manner of the present application, the sterilization device (13) comprises an ozone generator, an ultraviolet lamp and a timing switch element.

[0013] In another implementation manner of the present application, the temperature control device (15) comprises a temperature-sensitive sensor, a cooling element, a temperature-rising element and a temperature control processor (16); the temperature-sensitive sensor feeds back real-time temperature information in the printing container to the temperature control processor (16), and the temperature control processor outputs a control signal to start the temperature-rising element or the temperature-lowering element.

[0014] In another aspect of the present application, an ultrasonic 3D printing method is provided, which is applied to the ultrasonic 3D printing device described above, and comprises: mixing a polymer material, a bioactive ingredient and a sound-sensitive agent according to a preset ratio to obtain bio-ink; conveying the bio-ink into a bio-ink container of a forming module or a site to be filled by a living body; designing a model through a control unit, digitally cutting a product model according to requirements of a printing product, so as to set a printing path; setting an ultrasonic frequency or intensity required by 3D printing by using a focused ultrasonic wave control unit, so that bio-ink at a focal point part in the printing path is quickly solidified; driving the focused ultrasonic transducer to constantly change the focal point through three-dimensional movement of a slider in a movement module, so that bio-ink at different spatial positions in the printing path is solidified, and a three-dimensional structure model of the printing product is obtained.

[0015] In another implementation manner of the present application, characterized in that it further comprises: monitoring a printing process of the three-dimensional structure model through a camera in an auxiliary function module, and adjusting relevant printing parameters in real time according to a printing state, so as to ensure smooth printing.

[0016] In another implementation manner of the present application, it further comprises: controlling a sterilization device according to requirements of the printing product, so as to ensure a sterile state of the printing process and protect the product; and maintaining a constant temperature in a forming cabin through a temperature control device, so as to ensure continuous and stable printing, and reduce differences in forming effects caused by temperature changes.

[0017] The ultrasonic 3D printing device of the present application adopts an integrated ultrasonic transducer emission module, can quickly switch different ultrasonic transducers of different frequencies according to different categories or structural requirements of bio-ink, adopts a slider capable of three-dimensional directional movement, has micron-level positioning accuracy, improves the accuracy of ultrasonic bio-3D printing, has high modularity, can quickly replace components according to different scene requirements, is also conducive to later maintenance, can reduce ultrasonic sound pressure by regulating ultrasonic frequency and intensity, and can regulate material forming temperature by adjusting the temperature of bio-ink or the forming cabin, so that the material has biological safety. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to make the skilled in the art better understand the technical solutions in the embodiments of the present application, the following will be combined with the drawings in the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and detailedly. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the embodiments of the present application, all the other embodiments obtained by the skilled in the art should belong to the scope of protection of the embodiments of the present application.

[0019] Fig. 1 is a schematic diagram of an ultrasonic 3D printing device according to an embodiment of the present application.

[0020] BRIEF DESCRIPTION OF DRAWINGS

[0021] 1- forming cabin, 2- bio-ink container, 3- bio-ink, 4- focused ultrasonic transducer group, 5- focused ultrasonic control unit, 6- slider, 7- x-axis screw guide rail, 8- y-axis screw guide rail, 9- z-axis screw guide rail, 10- displacement control unit, 11- high-definition camera, 12- high-definition display screen, 13- sterilization device, 14- timing switch, 15- temperature control device, 16- temperature control processor, 17- central power supply. DETAILED DESCRIPTION

[0022] In order to make the skilled in the art better understand the technical solutions in the embodiments of the present application, the following will be combined with the drawings in the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and detailedly. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the embodiments of the present application, all the other embodiments obtained by the skilled in the art should belong to the scope of protection of the embodiments of the present application.

[0023] Fig. 1 is a schematic diagram of an ultrasonic 3D printing device according to an embodiment of the present application.

[0024] Forming cabin (1), forming module, emission module, motion module, auxiliary function module, central power supply (17).

[0025] The forming module is arranged in the forming cabin (1) and includes a bio-ink container (2) and bio-ink (3). The bio-ink container (2) is used to hold the bio-ink (3) and printing initial products, and the bio-ink (3) is based on ultrasonic action to realize thermal curing.

[0026] Exemplarily, the forming module further includes a material forming platform. The material forming platform can be used for printing bio-ink material to quickly solidify on the platform, and different bio-ink containers (2) can be placed. The bio-ink container (2) can be used as a bio-ink carrier vessel to directly and quickly form a high-precision adjustable and stable three-dimensional structure during printing, so that the fine three-dimensional structure of the active material can be safely and effectively constructed in vivo.

[0027] Specifically, the bio-ink (3) comprises a polymer material, a bioactive ingredient, and a sonosensitizer. The polymer material comprises one or more of unsaturated polymer, agar, and poly (N-isopropyl acrylamide), etc.; the bioactive ingredient comprises one or more of cells, polypeptides, proteins, nucleic acids, metal oxide particles, or metal elements; the sonosensitizer is a metal oxide particle or an ultrasound-sensitive molecular compound; further, various materials for 3D printing can be formulated into ultrasound-responsive bio-ink in a certain ratio according to requirements and placed in a bio-ink container.

[0028] The emitting module comprises a focused ultrasonic transducer group (4) for precise solidification printing of bio-ink at different spatial positions, which is mounted on the slider (6) of the three-dimensional motion guide rail in the motion module through a connecting piece.

[0029] The motion module comprises a guide rail with a three-dimensional motion function and a displacement control unit (10), which cuts a preset three-dimensional model to output path instructions to control the displacement of the slider (6) mounted on the guide rail to drive the focused ultrasonic transducer (4) to precisely solidify bio-ink at different spatial positions.

[0030] Exemplarily, a product model is designed by computer-aided design (CAD) technology, and the model is digitally cut and divided according to the required scheme, and then the instructions are output to control the displacement of the slider, which further drives the ultrasonic transducer to focus the bio-ink at different spatial positions for solidification to perform 3D printing.

[0031] The auxiliary function module comprises a high-definition camera (11), a high-definition display screen (12), a sterilization device (13), and a temperature control device (15). The high-definition camera (11) records the scene in the range of focused ultrasonic printing in real time and transmits the picture to the connected high-definition display screen (12) to feedback the real-time printing state for adjusting the printing parameters. The sterilization device (13) is used for killing microorganisms in the printing environment. The temperature control device (15) is used for maintaining the constant temperature in the printing environment. The auxiliary functions include real-time high-definition monitoring, sterilization, and temperature control functions, which can be selectively turned on according to the actual application requirements.

[0032] The central power supply (17) is used for providing the power required by the ultrasonic 3D printing device.

[0033] The ultrasonic 3D printing device of the application adopts an integrated ultrasonic transducer emission module, can quickly switch different frequency ultrasonic transducers for different types or structural requirements of biological ink, adopts a slider capable of three-dimensional motion, has micron-level positioning accuracy, and improves the accuracy of ultrasonic biological 3D printing, has high modularity, can quickly replace components for different scene requirements, and is also beneficial to later maintenance, can reduce ultrasonic sound pressure by regulating ultrasonic frequency and intensity, and can regulate material forming temperature by adjusting biological ink or controlling the temperature of the forming cabin, so as to have biological safety.

[0034] In another implementation manner of the application, the focused ultrasonic transducer group (4) is integrated with a plurality of focused ultrasonic transducers of different frequencies and power, can quickly switch different frequency ultrasonic waves for different types or structural requirements of biological ink, and in addition, the focused ultrasonic wave can realize three-dimensional solidification forming for thermosetting materials.

[0035] In another implementation manner of the application, the focused ultrasonic transducer group (4) is regulated by a focused ultrasonic control unit (5) to generate different power density ultrasonic focusing effects, and the ultrasonic transducer solidifies and prints biological ink at the focus position by emitting specific focused ultrasonic waves.

[0036] In another implementation manner of the application, the frequency range of the focused ultrasonic transducer group (4) is 20 kHz-50 MHz.

[0037] Exemplarily, the selection of focused ultrasonic frequency and intensity is to establish the corresponding relationship between focused ultrasonic frequency / power and ink forming effect through preliminary tests or experiments, screen out frequencies and intensities with high accuracy, low sound pressure and low sound heat, and develop corresponding ultrasonic transducers for 3D printing equipment, preferably 20 kHz, 100 kHz, 1 MHz, 3 MHz, 6 MHz and 10 MHz, and select ultrasonic frequency and intensity with the best forming effect for printing according to the selected relationship.

[0038] In another implementation manner of the application, the guide rail capable of three-dimensional motion includes an x-axis screw guide rail (7), a y-axis screw guide rail (8) and a z-axis screw guide rail (9), and the displacement of the slider (6) in the x, y and z axis directions drives the focused ultrasonic transducer group (4) to focus and print biological ink at different spatial positions.

[0039] In another implementation manner of the application, the sterilization device (13) includes an ozone generator, an ultraviolet lamp and a timing switch element.

[0040] In another implementation of the present invention, the temperature control device (15) includes a temperature sensor, a cooling element, a heating element, and a temperature control processor (16); the temperature sensor feeds back the real-time temperature information inside the printing container to the temperature control processor (16), and the temperature control processor outputs a control signal to start the heating element or the cooling element.

[0041] In another aspect of the present invention, an ultrasonic 3D printing method is provided, applied to the aforementioned ultrasonic 3D printing apparatus. The printing method includes the selection and preparation of ultrasonic responsive ink; digital cutting and partitioning of the printed product model; selection and application of focused ultrasonic frequency and intensity; and debugging and activation of auxiliary functions. Specific steps include:

[0042] The polymer material, bioactive ingredients, and sound-sensitive agent are mixed according to a preset ratio to obtain bio-ink.

[0043] For example, the material to be printed is made into a liquid or fluid, and a sound-sensitive agent is added and dispersed evenly to obtain bio-ink.

[0044] The bio-ink is delivered to the bio-ink container of the molding module or to the part of the organism to be filled.

[0045] The model is designed through the control unit, and the product model is digitally cut according to the requirements of the printed product in order to set the printing path.

[0046] By using a focused ultrasonic control unit to set the ultrasonic frequency or intensity required for 3D printing, the bio-ink at the focal point in the printing path can be rapidly cured.

[0047] For example, the ultrasonic frequency and intensity with the best molding effect are selected through preliminary experiments, and then the corresponding focused ultrasound is selected for 3D printing.

[0048] The three-dimensional movement of the slider in the motion module drives the focused ultrasonic transducer to continuously change its focus, causing the bio-ink at different spatial positions in the printing path to solidify, thus obtaining a three-dimensional structural model of the printed product.

[0049] In another implementation of the present invention, the method further includes: monitoring the printing process of the three-dimensional structural model through a camera in the auxiliary function module, and adjusting relevant printing parameters in real time according to the printing status to ensure smooth printing.

[0050] In another implementation of the present invention, the method further includes: controlling the sterilization device according to the requirements of the printed product to ensure the sterility of the printing process and protect the product; and maintaining a constant temperature in the molding chamber through a temperature control device to ensure the continuous and stable operation of the printing process and reduce the difference in molding effect caused by temperature changes.

[0051] In another aspect of the present application, the electronic device comprises a processor, a memory, and a communication bus, and a communications interface.

[0052] In which:

[0053] The processor, the memory, and the communications interface communicate with each other through the communication bus.

[0054] The communications interface is configured to communicate with other electronic devices or servers.

[0055] The processor is configured to execute a program, and specifically can execute the steps of any of the ultrasonic 3D printing methods described in the above embodiments.

[0056] Specifically, the program can include program code comprising computer operation instructions.

[0057] The processor can be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application. The one or more processors included in the smart device can be processors of the same type, such as one or more CPUs; or can be processors of different types, such as one or more CPUs and one or more ASICs.

[0058] The memory is configured to store the program. The memory can include a high-speed RAM memory, and can also include a non-volatile memory, such as at least one disk memory.

[0059] The program can specifically be used to cause the processor to execute the steps to implement any of the ultrasonic 3D printing methods described in the embodiments. The specific implementation of each step in the program can refer to the corresponding description of the steps and units executed by any of the ultrasonic 3D printing methods described above, and will not be described here. Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the devices and modules described above can refer to the corresponding process descriptions in the foregoing method embodiments.

[0060] The exemplary embodiments of the present application also provide a non-transitory computer-readable storage medium having computer instructions stored therein, wherein the computer instructions are used to cause a computer to execute the method of any of the embodiments of the present application.

[0061] The above-described methods according to embodiments of the application can be implemented in hardware, firmware, or software, or any combination thereof, and can be implemented as software storable on a recording medium which is readable from a general use computer, a special processor or programmable, or a special hardware (such as ASIC or FPGA) using a general use computer, a special processor or programmable hardware (such as ASIC or FPGA). It can be understood that the computer, the processor, the microprocessor controller or the programmable hardware include a storage component (for example, RAM, ROM, flash memory, etc.) which can store or receive software or computer code, when the software or computer code is accessed and executed by the computer, the processor or the hardware, the above-described methods are implemented. In addition, when the general use computer accesses the code for implementing the methods shown herein, the execution of the code will convert the general use computer into a special computer for executing the methods shown herein.

[0062] So far, specific embodiments of the present application have been described. Other embodiments are within the scope of the following claims. In some cases, the acts recited in the claims can be performed in a different order and still achieve desirable results. Additionally, the processes depicted in the figures do not necessarily require the particular order shown, or sequential order, to achieve the desired results. In certain implementations, multitasking and parallel processing can be advantageous.

[0063] It should be noted that all directional directions (such as up, down, left, right, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, motion condition, etc. between components in a certain specific posture (as shown in the drawings), if the specific posture changes, the directional directions also change accordingly.

[0064] In the description of the present application, the terms "first", "second" are only used for the convenience of describing different components or names, and cannot be understood as indicating or implying the order relationship, relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can be explicitly or implicitly included at least one of the features.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0066] It should be noted that, although the specific embodiments of the present application are described in detail with reference to the accompanying drawings, it should not be understood as limiting the scope of protection of the present application. Various modifications and variations made by those skilled in the art within the scope described in the claims are still within the scope of protection of the present application.

[0067] The examples of the embodiments of the present application are intended to simply illustrate the technical features of the embodiments of the present application, so that those skilled in the art can directly understand the technical features of the embodiments of the present application, and are not improper limitations of the embodiments of the present application.

[0068] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An ultrasonic 3D printing device, characterized by, The application relates to a 3D printing device based on focused ultrasound. The forming module is arranged in the forming cabin (1) and comprises a bio-ink container (2) for containing bio-ink (3) and printing initial products, and the bio-ink (3) is based on ultrasonic action to realize thermal curing. The emitting module comprises a focused ultrasonic transducer group (4) for accurately curing and printing bio-ink at different spatial positions, and the focused ultrasonic transducer group (4) is installed on a slider (6) of a three-dimensional motion guide rail in the motion module through a connecting piece. The motion module comprises a guide rail with a three-dimensional motion function and a displacement control unit (10), the displacement control unit (10) cuts a preset three-dimensional model to output path instructions, controls the slider (6) installed on the guide rail to displace, and drives the focused ultrasonic transducer (4) to accurately cure bio-ink at spatial positions. The auxiliary function module comprises a high-definition camera (11), a high-definition display screen (12), a sterilization device (13) and a temperature control device (15), the high-definition camera (11) records a scene in a focused ultrasonic printing range in real time, transmits a picture to the connected high-definition display screen (12) to feed back a real-time printing state, and adjusts printing parameters; the sterilization device (13) is used for killing microorganisms in a printing environment; and the temperature control device (15) is used for maintaining the constancy of temperature in the printing environment. The central power supply (17) is used for providing power required by the ultrasonic 3D printing device. The focused ultrasonic transducer group (4) integrates a plurality of focused ultrasonic transducers with different frequencies.

2. The apparatus of claim 1, wherein, The focused ultrasonic transducer group (4) is regulated by a focused ultrasonic control unit (5) and is used for generating focused ultrasonic effects with different power densities.

3. The apparatus of claim 2, wherein, The frequency range of the focused ultrasonic transducer group (4) is 20 kHz-50 MHz.

4. The apparatus of claim 3, wherein, The guide rail with the three-dimensional motion function comprises an x-axis screw guide rail (7), a y-axis screw guide rail (8) and a z-axis screw guide rail (9).

5. The apparatus of claim 1, wherein, The displacement of the slider (6) in x, y and z axial directions drives the focused ultrasonic transducer group (4) to focus and print bio-ink at different spatial positions. The sterilization device (13) comprises an ozone generator, an ultraviolet lamp and a timing switch element.

6. The apparatus of claim 1, wherein, The temperature control device (15) comprises a temperature-sensitive sensor, a cooling element, a temperature-rising element and a temperature control processor (16).

7. The apparatus of claim 1, wherein, The temperature control processor outputs a control signal to start the temperature-rising element or the cooling element through the temperature-sensitive sensor to feed back real-time temperature information in a printing container to the temperature control processor (16). The application further relates to a bio-ink preparation method.

8. An ultrasonic 3D printing method applied to the ultrasonic 3D printing device of claim 1, characterized in that, The bio-ink is delivered into a bio-ink container of the forming module or a site to be filled of a living body. ​ ​ The model is designed by the control unit, and the product model is digitally cut according to the requirements of the printed product to set the printing path; The focusing ultrasonic control unit sets the ultrasonic frequency or intensity required for 3D printing, so that the biological ink at the focal point in the printing path quickly responds and solidifies; Through the three-dimensional movement of the slider in the motion module, the focusing ultrasonic transducer constantly changes the focal point, so that the biological ink at different spatial positions in the printing path solidifies, and the three-dimensional structure model of the printed product is obtained.

9. The method of claim 8, wherein, Further comprising: The printing process of the three-dimensional structure model is monitored by the camera in the auxiliary function module, and the related printing parameters are adjusted in real time according to the printing state to ensure the smooth progress of printing.

10. The method of claim 9, wherein, Further comprising: According to the requirements of the printed product, the sterilization device is controlled to ensure the sterile state of the printing process and to protect the product; The temperature control device maintains the constant temperature in the forming chamber, ensures the continuous and stable progress of the printing process, and reduces the differences in forming effect caused by temperature changes.

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