Method and equipment for monitoring structural-mechanical composite parameters in 3D printing process

Abstract

The present invention provides a method and device for monitoring the structural-mechanical composite parameters of a 3D printing process. The method is applied to a 3D imaging detector connected to a 3D printing platform, and the 3D imaging detector is used to obtain process parameters of the 3D printing platform during the printing process. The process parameters are then input into a pre-established computational model, and the computational model is used to calculate mechanical characteristic parameters corresponding to the process parameters. The mechanical characteristic parameters include a first mechanical parameter and a second mechanical parameter. The method can calculate and obtain two mechanical characteristic parameters of a printed material structure during the 3D printing process, calculating and obtaining the mechanical properties of the printed material structure throughout the entire process. This method can measure and modulate the 3D printed material even in complex structural environments, enabling decoding and regulation of the mechanism by which the printed structure and viscoelasticity synergistically influence tissue morphogenesis. This method provides technical support for monitoring the mechanical environment of printed structures in the field of biological 3D printing.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing structure technology, and in particular to a method and device for monitoring structural-mechanical composite parameters in a 3D printing process. Background Art

[0002] Bio-3D printing can construct biomimetic structures of tissues and organs based on digital models, providing technical support for regulating geometric information to reconstruct tissues and organs (Nat Mater. 2021). The development and construction of tissues and organs is a spatiotemporal process coordinated by geometric, mechanical, and biochemical signals (Nature reviews, 2021). The mechanical environment is a key factor in regulating the fate and morphogenesis of stem cells.

[0003] Viscoelasticity is a universal characteristic of living tissues and the extracellular matrix (ECM). It manifests as a time-dependent response to loading or phase change, influencing cell spreading, growth, proliferation, and fate. During the printing process, the viscoelasticity of high-water-content biomaterials / bioinks is affected by factors such as nozzle temperature and platform temperature. Under the influence of forces such as gravity, compression, and tension, the structure undergoes time-dependent deformation, including creep and stress relaxation. However, existing mechanical testing methods, such as rheology instruments, can measure the viscoelasticity of fixed macroscopic materials and atomic force microscopy can measure the viscoelasticity of single molecules and cells. However, there is a lack of effective methods for measuring the viscoelasticity of materials at scales of 10 to 1000 microns, a scale critical for tissue morphogenesis. The lack of tools to measure and modulate the complex mechanical environment within 3D-printed structures has hindered the decoding and regulation of the mechanisms by which the printed structure and viscoelasticity synergistically influence tissue morphogenesis. Consequently, 3D bioprinting still faces a technical bottleneck in monitoring the mechanical environment of the printed structure. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a method and device for monitoring the structural-mechanical composite parameters of a 3D printing process, which can monitor the mechanical characteristic parameters of a 3D printed material structure at high speed or in real time.

[0005] In the first aspect, an embodiment of the present invention provides a method for monitoring structural-mechanical composite parameters of a 3D printing process, which is applied to a three-dimensional imaging detector connected to a 3D printing platform. The method includes: using the three-dimensional imaging detector to obtain process parameters of the 3D printing platform during the printing process; the process parameters correspond to the printed structure; the process parameters are input into a pre-established calculation model, and the mechanical characteristic parameters corresponding to the process parameters are calculated by the calculation model; wherein the mechanical characteristic parameters include a first mechanical parameter and a second mechanical parameter; the process parameter corresponds to the first mechanical parameter or the second mechanical parameter; the first mechanical parameter is used to characterize the deformation characteristics corresponding to the material structure of the printed structure, and the second mechanical parameter is used to characterize the mechanical characteristics of the material structure of the printed structure related to the vibration caused by external excitation.

[0006] In combination with the first aspect, an embodiment of the present invention provides a first possible implementation method of the first aspect, wherein, when the process parameter corresponds to the first mechanical parameter, the step of using a three-dimensional imaging detector to obtain the process parameter of the 3D printing platform during the printing process includes: using the three-dimensional imaging detector to obtain a three-dimensional high-resolution image of the printed structure during the printing process; quantifying the parameter changes of the printed structure at different time points based on the three-dimensional high-resolution image, establishing a time-dependent small deformation, and obtaining the process parameter corresponding to the first mechanical parameter; wherein the process parameter includes the squareness feature of the printed structure, and the squareness feature is determined based on the three-dimensional high-resolution image data.

[0007] In combination with the first aspect, an embodiment of the present invention provides a second possible implementation of the first aspect, wherein the steps of quantifying parameter changes of the printed structure at different time points based on the three-dimensional high-resolution image, establishing time-dependent small deformations, and obtaining process parameters corresponding to the first mechanical parameters include: obtaining three-dimensional high-resolution image data of the printing layer of each section of the printed structure during the printing process; obtaining the squareness characteristics of the channel cross-section of each section of the printed structure based on the three-dimensional high-resolution image data; and storing the squareness characteristics as the process parameters of the first mechanical parameter.

[0008] In combination with the first aspect, an embodiment of the present invention provides a third possible implementation of the first aspect, wherein the process parameters are input into a pre-established calculation model, and the step of calculating the mechanical characteristic parameters corresponding to the process parameters through the calculation model includes: determining the output result of the calculation model based on the squareness characteristics of each segment of the printed structure in the process parameters and the moment information corresponding to the three-dimensional high-resolution image data; comparing the output result with a preset comparison parameter, and determining the first mechanical parameter of the printed structure based on the comparison result.

[0009] In combination with the first aspect, an embodiment of the present invention provides a fourth possible implementation of the first aspect, wherein the pre-established calculation model includes:

[0010]

[0011] P r Used to indicate the squareness characteristics of the channel cross section, It is used to indicate the multiplication of the diameter ratio of the upper and lower cross-section channels in each section of the printed structure during the printing process. is the ratio of the measured channel height of the printed structure to the preset layer height, and h0 is the preset layer height; the step of determining the output result of the calculation model based on the squareness characteristics of each section of the printed structure in the process parameters and the time information corresponding to the three-dimensional high-resolution image data includes: determining the multiplication parameter of the ratio of the upper and lower cross-section channel diameters of the channel in each section of the structure and the squareness mean at the current moment based on the squareness characteristics of each section of the printed structure and the time information corresponding to the three-dimensional high-resolution image data; determining the layer height cardinality corresponding to each section of the printed structure based on the preset layer height parameter and the layer height data of the printed structure; and determining the output result of the calculation model based on the squareness mean, the multiplication parameter, and the layer height cardinality.

[0012] In combination with the first aspect, an embodiment of the present invention provides a fifth possible implementation of the first aspect, wherein a dynamic excitation source is integrated on the three-dimensional imaging detector, and the dynamic excitation source is controlled by timing to perform dynamic excitation operations on the printed structure during the 3D printing process; when the process parameter corresponds to the second mechanical parameter, the step of using the three-dimensional imaging detector to obtain the process parameter of the 3D printing platform during the printing process includes: responding to the dynamic excitation operation applied by the 3D printing platform when printing each section of the printed structure; measuring the detection signal corresponding to the dynamic excitation operation at each position of each section of the printed structure through the three-dimensional imaging detector; wherein each section of the printed structure includes a multi-layer printed structure; the detection signal includes the vibration distribution corresponding to the elastic wave generated by the printing structure based on the dynamic excitation operation; the detection signal is preprocessed to obtain a structural-mechanical signal corresponding to each position of the printed structure; wherein the structural-mechanical signal includes a phase value parameter and an amplitude parameter; and the phase value parameter and amplitude parameter of each position are stored as the process parameters of the printed structure corresponding to the second mechanical parameter.

[0013] In combination with the first aspect, an embodiment of the present invention provides a sixth possible implementation of the first aspect, wherein the detection signal is acquired through the MB scanning mode, and the detection signal corresponds to sub-detection signals at multiple moments; the process parameters are input into a pre-established calculation model, and the step of calculating the mechanical characteristic parameters corresponding to the process parameters through the calculation model includes: determining the vibration information corresponding to the printing structure at the current position based on the sub-detection signals and phase value parameters at multiple moments corresponding to each position; wherein the vibration information includes the vibration velocity and vibration displacement of the printing structure; based on the vibration information, determining the elastic frequency of the printing structure; based on the elastic frequency, determining the elastic wave velocity at each elastic frequency, and drawing a wave velocity dispersion curve; calculating the second mechanical parameter corresponding to the printing structure based on the wave velocity dispersion curve; wherein the second mechanical parameter is used to calculate the axial elastic modulus and the lateral elastic modulus.

[0014] In combination with the first aspect, an embodiment of the present invention provides a seventh possible implementation of the first aspect, wherein the step of determining the vibration information corresponding to the printing structure at the current position based on the sub-detection signals and phase value parameters at multiple moments corresponding to each position includes: determining the phase change corresponding to each moment based on the phase value parameters corresponding to two adjacent moments of the current position; calculating the vibration speed of the printing structure at each moment based on the phase change; determining the vibration displacement corresponding to each moment based on the vibration speed, and constructing a time-space displacement map based on the vibration displacement at each moment to obtain vibration information.

[0015] In combination with the first aspect, an embodiment of the present invention provides an eighth possible implementation of the first aspect, wherein the elastic frequency of the printed structure is determined based on vibration information; based on the elastic frequency, the step of determining the elastic wave velocity at each elastic frequency includes: performing a two-dimensional discrete Fourier transform on the space-time displacement map to obtain a frequency domain-wave number domain map; extracting the maximum value of the frequency value from the frequency domain-wave number domain map, and normalizing the maximum value to obtain an energy distribution curve; determining the target frequency value corresponding to the highest energy point in the energy distribution curve; based on the frequency domain-wave number domain map, determining the ratio of the frequency corresponding to the target frequency value to the wave number domain as the elastic wave velocity; the elastic wave velocity includes the shear wave propagation velocity and the Rayleigh wave propagation velocity.

[0016] In the second aspect, an embodiment of the present invention also provides a structural-mechanical composite parameter monitoring device for a 3D printing process, and the device is configured in the above method; the device includes an excitation module, a three-dimensional imaging detection module and a signal processing module; the excitation module is used to generate an excitation signal when obtaining the process parameter corresponding to the second mechanical parameter, so that the printed structure generates an elastic wave; the three-dimensional imaging detection module is connected to the excitation module, and is used to emit imaging detection light according to the triggering operation of the excitation signal, and to obtain an imaging signal corresponding to the imaging detection light; the signal processing module is connected to the three-dimensional imaging detection module, and is used to process the imaging signal obtained by the three-dimensional imaging detection module, and extract the process parameter corresponding to the first mechanical parameter or the process parameter corresponding to the second mechanical parameter from the imaging signal to determine the mechanical characteristic parameters corresponding to the process parameter of the printed structure.

[0017] The embodiments of the present invention bring the following beneficial effects: The present invention provides a structural-mechanical composite parameter monitoring method and device for a 3D printing process, which utilizes a three-dimensional imaging detector to calculate and obtain two mechanical characteristic parameters of a printed material structure during the 3D printing process, so as to calculate and obtain the mechanical properties of the 3D printed material structure throughout the entire process. Even if the 3D printed material is in a complex structural environment, it can be measured and modulated. In addition, a measurement and modulation tool for the complex mechanical environment in a 3D printed structure is provided, which can realize the decoding and regulation of the printed structure and viscoelasticity that synergistically influence the tissue morphogenesis mechanism, providing technical support for monitoring the mechanical environment of the printed structure in the field of biological 3D printing.

[0018] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A flow chart of a method for monitoring structural-mechanical composite parameters of a 3D printing process provided by an embodiment of the present invention;

[0022] Figure 2 A flowchart of another method for monitoring structural-mechanical composite parameters of a 3D printing process provided by an embodiment of the present invention;

[0023] Figure 3 A schematic diagram of an abstract modeling of a printed structure under different mechanical environments provided by an embodiment of the present invention;

[0024] Figure 4 Another schematic diagram of abstract modeling of a printed structure under different mechanical environments provided by an embodiment of the present invention;

[0025] Figure 5 Another schematic diagram of abstract modeling of a printed structure under different mechanical environments provided by an embodiment of the present invention;

[0026] Figure 6 XZ cross-sectional images of different numbers of layers of gelatin / alginate printed using P-OCT provided in an embodiment of the present invention;

[0027] Figure 7 XY cross-sectional diagram at 0.1 mm from the bottom surface when P-OCT detects different numbers of gelatin / alginate printing layers provided by an embodiment of the present invention;

[0028] Figure 8 A flow chart of another method for monitoring structural-mechanical composite parameters of a 3D printing process provided by an embodiment of the present invention;

[0029] Figure 9 A schematic diagram of a structural-mechanical composite parameter monitoring device for a 3D printing process provided by an embodiment of the present invention;

[0030] Figure 10 A schematic diagram of the integration of a p-OCE probe and a printing device provided in an embodiment of the present invention;

[0031] Figure 11 A diagram showing the working principle of a structural-mechanical composite parameter monitoring device for a 3D printing process provided by an embodiment of the present invention;

[0032] Figure 12 A schematic structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] Bio-3D printing can construct biomimetic structures of tissues and organs based on digital models, providing technical support for regulating geometric information to reconstruct tissues and organs (Nat Mater. 2021). The development and construction of tissues and organs is a spatiotemporal process coordinated by geometric, mechanical, and biochemical signals (Nature reviews, 2021). The mechanical environment is a key factor in regulating the fate and morphogenesis of stem cells.

[0035] Viscoelasticity is a universal characteristic of living tissues and the extracellular matrix (ECM). It manifests as a time-dependent response to loading or phase change, influencing cell spreading, growth, proliferation, and fate. During the printing process, the viscoelasticity of high-water-content biomaterials / bioinks is influenced by factors such as nozzle temperature, platform temperature, and printing pressure. Under the action of forces such as gravity, compression, and tension, the structure undergoes time-dependent deformation, including creep and stress relaxation. However, existing mechanical testing methods, such as rheology instruments, can measure the viscoelasticity of fixed macroscopic materials and atomic force microscopy can measure the viscoelasticity of single molecules and cells. However, there is a lack of effective methods for measuring the viscoelasticity of materials at scales of 10 to 1000 microns, a scale critical for tissue morphogenesis. The lack of tools to measure and modulate the complex mechanical environment within 3D-printed structures has hindered the understanding and regulation of the mechanisms by which printed structures and viscoelasticity synergistically influence tissue morphogenesis. 3D bioprinting still faces a technical bottleneck: the inability to monitor the mechanical environment of printed structures.

[0036] Based on this, the embodiments of the present invention provide a method and device for monitoring structural-mechanical composite parameters of a 3D printing process, which can perform high-speed or real-time monitoring of the mechanical characteristic parameters of the material structure of the 3D printed structure.

[0037] To facilitate understanding of this embodiment, a method for monitoring structural-mechanical composite parameters of a 3D printing process disclosed in an embodiment of the present invention is first described in detail. The method is applied to a three-dimensional imaging detector connected to a 3D printing platform.

[0038] Figure 1 FIG. 1 shows a flow chart of a method for monitoring structural-mechanical composite parameters of a 3D printing process provided by an embodiment of the present invention. Figure 1 As shown, the method includes the following steps:

[0039] Step S102: using a three-dimensional imaging detector to obtain process parameters of the 3D printing platform during the printing process.

[0040] Step S104 : inputting the process parameters into a pre-established calculation model, and calculating the mechanical characteristic parameters corresponding to the process parameters through the calculation model.

[0041] Among them, the process parameters correspond to the printing structure, which are the structural parameters of the 3D printing platform during the process of printing the printing structure; the mechanical characteristic parameters include the first mechanical parameter and the second mechanical parameter, and the process parameters correspond to the first mechanical parameter or the second mechanical parameter; specifically, the mechanical characteristic parameters of the printing structure include the above-mentioned first mechanical parameter and the second mechanical parameter, the first mechanical parameter is used to characterize the mechanical deformation characteristics related to the deformation caused by the material structure of the printing structure and its own gravity, surface tension, etc., and the second mechanical parameter is used to characterize the mechanical characteristics related to the vibration caused by external excitation of the material structure of the printing structure.

[0042] In an embodiment of the present invention, a three-dimensional imaging detector can be used to determine the first mechanical parameter or the second mechanical parameter of the printed structure as required. In this case, different process parameters can be obtained through the three-dimensional imaging detector.

[0043] Specifically, in order to achieve real-time monitoring of the mechanical properties of the printed structure during the biological 3D printing process, the three-dimensional imaging detector of the embodiment of the present invention adopts optical coherence tomography (OCT), such as swept-frequency OCT, spectral domain OCT, time-domain OCT, and full-field OCT integrated with the printing platform, called Printing platform-OCT, referred to as p-OCT, or ultrasound imaging, photoacoustic imaging, and photoacoustic microscopy acquisition technology integrated with the printing platform. The three-dimensional imaging detector is used to obtain a three-dimensional high-resolution image of the printed structure during the printing process, and the corresponding process parameters are determined based on the obtained three-dimensional high-resolution image. The process parameters are input into a pre-established calculation model to calculate the first mechanical parameters of the printed structure.

[0044] In addition, an embodiment of the present invention also integrates a dynamic excitation source on a three-dimensional imaging detector to form optical coherence elastography (OCE), which is then integrated with biological 3D printing technology, referred to as p-OCE. By combining the microscopic fault structure-mechanical composite imaging characteristics of OCE with the discrete manufacturing principles of 3D printing, composite imaging, characterization, and feedback control of printed structure-mechanics are achieved. Parameters during the 3D printing process are obtained through optical coherence elastography, and the mechanical properties of the printed structure are evaluated according to a pre-established calculation model, such as a viscoelastic creep model, to obtain a second mechanical characteristic parameter.

[0045] An embodiment of the present invention provides a method for monitoring structural-mechanical composite parameters of a 3D printing process. A three-dimensional imaging detector can be used to calculate and obtain two mechanical characteristic parameters of a printed material structure during the printing process of a 3D printed structure. Corresponding printing process parameters can be obtained as needed, and then a first mechanical characteristic parameter or a second mechanical characteristic parameter of the 3D printed material structure can be determined based on the obtained printing process parameters. This allows for calculation and acquisition of the mechanical properties of the 3D printed material structure throughout the entire process. This allows for measurement and modulation of 3D printed materials even in complex structural-mechanical environments, enabling decoding and regulation of the printed structure and the viscoelasticity's synergistic influence on tissue morphogenesis. This provides technical support for monitoring the mechanical environment of printed structures in the field of biological 3D printing.

[0046] Furthermore, based on the above method embodiment, the embodiment of the present invention also provides another method for monitoring the structural-mechanical composite parameters of a 3D printing process. This method is to introduce a specific monitoring process when the process parameter corresponds to the first mechanical parameter. Figure 2 FIG. 1 is a flow chart showing another method for monitoring structural-mechanical composite parameters of a 3D printing process provided by an embodiment of the present invention. Figure 2 As shown, the method includes the following steps:

[0047] Step S202 : using a three-dimensional imaging detector to obtain a three-dimensional high-resolution image of the printed structure during the printing process.

[0048] Step S204 , quantifying parameter changes of the printed structure at different time points based on the three-dimensional high-resolution image, establishing a time-dependent micro-deformation, and obtaining a process parameter corresponding to the first mechanical parameter.

[0049] In a specific implementation, the embodiment of the present invention can use a three-dimensional imaging detector to detect the printed structure during the printing process, detect the time-dependent micro-deformations during the printing process, characterize the mechanical state of the printed material structure, input the process parameters corresponding to the mechanical state into a pre-established deformation model, and calculate the first mechanical parameter. Among them, the embodiment of the present invention uses the shape change of the vertical channel in the printed material structure as the modeling object. During the printing process, the viscoelastic material undergoes time-dependent deformation and stress release under the action of gravity, surface tension, etc., resulting in a smaller cross-sectional area of ​​the vertical channel, an increased roundness, and a reduced height. Based on the above geometric deformation characteristics, the first mechanical parameter P is defined. VE .

[0050] In a specific implementation, the three-dimensional high-resolution image can be OCT data obtained through optical coherence tomography technology. The embodiment of the present invention takes the three-dimensional high-resolution image as OCT data for illustration, wherein the OCT data of the printing layer of each section of the printing structure during the printing process can be obtained, and based on the OCT data, the squareness characteristics of the channel cross-section of each section of the printing structure are obtained, and the squareness characteristics are stored as process parameters of the first mechanical parameter.

[0051] Specifically, embodiments of the present invention utilize optical coherence to collect data from the 3D printing platform during the printing process of a printed structure. This allows observation of the creep, collapse, displacement, and fusion of viscoelastic materials under the effects of gravity, pressure, and tension as the printed structure is stacked. This results in reduced vertical channel height, smaller cross-sectional areas, and rounded shapes. Furthermore, during real-time OCT data acquisition of the printed material structure during its printing process, OCT data corresponding to the squareness characteristics of each segment of the printed structure can be obtained, representing the aforementioned process parameters of the printed structure.

[0052] Step S206 : determining the output result of the calculation model according to the squareness characteristics of each printed structure in the process parameters and the time information corresponding to the three-dimensional high-resolution image data.

[0053] After obtaining the above-mentioned process parameters, they can be input into a pre-established calculation model, which is a time-dependent deformation model. Among them, the moment information of the three-dimensional high-resolution image data corresponding to the squareness characteristics of each section of the printed structure in the above-mentioned process parameters must also be input into the time-dependent deformation model to obtain the output result of the deformation model.

[0054] Specific, pre-built time-dependent deformation models include:

[0055]

[0056] Among them, P r is the squareness of the channel cross section, which can be expressed as: L is the perimeter of each printing channel section, A is the area of ​​each printing channel section, is the average squareness of each section. d is the diameter of the channel section, It is the product of the ratio of the upper and lower cross-section channel diameters of each channel in the structure during the printing process. c is the single-segment printing time, and Δt is the time interval between printing and image acquisition (Δt is set according to the material deformation speed). i (i×t c ) is the lower cross-sectional diameter of the three-dimensional channel obtained by the three-dimensional imaging detector immediately after printing the i-th segment, d′ i (i×t c+Δt) is the upper cross-sectional diameter of the three-dimensional channel obtained by the three-dimensional imaging detector at interval Δt after printing the i-th segment, is the ratio of the measured channel height of the printed structure to the preset layer height, and h0 is the preset layer height.

[0057] The number of printing layers for each printed structure is set according to the penetration depth of the three-dimensional imaging detector, with the minimum setting being 2 layers, which can form a square channel. The number of printing layers for each printed structure needs to be set to an even number.

[0058] Based on the definitions of the variables in the aforementioned model, the present embodiment first determines the squareness characteristics of each printed structure segment and the time information corresponding to the 3D high-resolution image data. The multiplication parameter of the upper and lower channel diameter ratios within each segment and the current mean squareness value are then determined. The layer height cardinality corresponding to each printed structure segment is then determined based on the preset layer height parameters and the layer height data of the printed structure. The output of the deformation model is then determined based on the mean squareness value, the multiplication parameter, and the layer height cardinality.

[0059] Step S208 : comparing the output result with a preset comparison parameter, and determining a first mechanical parameter of the printed structure based on the comparison result.

[0060] Specifically, the feature P is calculated based on the 2D image at the end of printing time using the above formula r , the corresponding P at this moment r The value can reflect the printability of the material, and the output result P of the above deformation model VE The value can reflect the initial viscoelasticity of the printed material and the stress relaxation characteristics within the structure. Specifically, Figure 3 、 Figure 4 、 Figure 5 The abstract modeling diagrams of the printed structure under different mechanical environments are shown respectively. VE When the value is ≥1.1, the material creep is small and the stress relaxation is slow. The printed material at this time will cause the extruded filament structure to be distorted, and the printing channel will be a square column with an irregular surface, such as Figure 5 When 0.9 <P VE When the value is <1.1, the creep of the material is moderate, the surface of the extruded filament is smooth and the layer thickness is stable. At this time, the printing channel structure of the printing material is close to a square column, such as Figure 4 When P VE When the value is ≤0.9, the material creep is large, and the collapse and roundness of the printing channel of the printing material increase, approaching an inverted cone cylinder, such as Figure 3 At this point, the first mechanical parameters such as the printability characteristic parameters of the printed material structure and the initial viscoelasticity of the material and the stress relaxation characteristic parameters within the structure can be obtained.

[0061] In practical applications, different gel states, such as over-gel, normal gel, and under-gel, have different local stress relaxation and creep states of viscoelastic materials and exhibit different characteristics in structural deformation. Figure 6 The XZ cross-sectional images of different layers of gelatin / alginate printed by p-OCT are shown. Figure 6 The structural diagrams of different printed layers in XZ and XY sections observed by p-OCT under different gel states are given. Figure 6 From top to bottom: over-gel, under-gel, and normal gel. Figure 7 The XY cross-sectional diagram at 0.1 mm from the bottom surface when p-OCT detects different numbers of gelatin / alginate printing layers is shown. Figure 7 From top to bottom: over-gel, under-gel, and normal gel.

[0062] Another structural-mechanical composite parameter monitoring method for a 3D printing process provided by an embodiment of the present invention is based on the viscoelastic mechanism of printed structure deformation, and establishes a method for defining and regulating the viscoelastic state of a printed material structure by detecting time-dependent deformation. The OCT technology is integrated with the printing platform, and structural images are obtained during the printing process of the printed structure to provide feedback and regulate the mechanical state of the printed material structure, providing a new method for regulating tissue morphogenesis and laying a technical foundation for the recursive printing of new biological components.

[0063] Furthermore, based on the above embodiment, another embodiment of the present invention provides another method for monitoring structural-mechanical composite parameters in a 3D printing process. This method introduces a specific monitoring process when a process parameter corresponds to a second mechanical parameter. In this method, a dynamic excitation source is integrated into the 3D imaging detector. The dynamic excitation source is controlled by timing to dynamically excite the printed structure during the 3D printing process. Figure 8 FIG. 1 is a flow chart showing another method for monitoring structural-mechanical composite parameters of a 3D printing process provided by an embodiment of the present invention. Figure 8 As shown, the method includes the following steps:

[0064] Step S302 , responding to the dynamic excitation operation applied by the 3D printing platform when printing each section of the printed structure.

[0065] Step S304 : measuring the detection signal corresponding to each position of each section of the printed structure based on the dynamic excitation operation by a three-dimensional imaging detector.

[0066] In a specific implementation, an embodiment of the present invention utilizes a dynamic excitation source integrated into a 3D imaging detector to apply dynamic excitation to the printed structure during the printing process on a 3D printing platform, inducing elastic waves within the printed structure. The 3D imaging detector then measures the propagation velocity and vibration displacement of the elastic waves to obtain the aforementioned detection signal, which includes the vibration distribution corresponding to the elastic waves generated by the dynamic excitation within the printed material structure. A second mechanical parameter of the printed material structure is then calculated based on a pre-established viscoelastic creep model. Based on the measured vibration distribution within the printed material structure under dynamic excitation, the propagation of the elastic waves within the printed material structure is visually reconstructed, achieving composite imaging of the printed material structure and mechanics.

[0067] Specifically, each printed structure during the printing process includes multiple layers. A dynamic excitation source integrated into the 3D imaging detector performs dynamic excitation operations on the printed structure during the printing process, controlled by timing. This dynamic excitation generation and detection is applied to each printed structure segment. The number of printed layers, N, for each printed structure segment is set based on the penetration depth of the 3D imaging detector, where N is equal to the integer of the result of dividing the penetration depth by the thickness of each layer. Based on the dynamic excitation operation, elastic waves are induced within the printed structure. The 3D imaging detector acquires detection signals at each position of each printed structure segment, and a second mechanical parameter is calculated based on the process parameters indicated by these detection signals.

[0068] Among them, the embodiment of the present invention excites the printed structure to generate tiny vibrations through piezoelectric excitation, ultrasonic excitation or jet excitation, induces elastic waves in the printed structure sample, and uses p-OCE detection to track the elastic waves of the printed structure sample, and then quantitatively evaluates the mechanical properties of the printed tissue based on the viscoelastic creep modeling of the printed material. When an external excitation source is used to dynamically excite the printed structure sample at a specific position, the material of the printed structure generates tiny elastic vibrations at the excitation point. The elastic vibration propagates from the excitation position to the surrounding medium inside or near the surface of the sample in the form of elastic waves. Due to the different propagation positions of the elastic waves, different types of elastic waves may be generated in the material. The elastic waves propagating inside thicker samples are called body waves, including compression waves and shear waves, while the elastic waves propagating near the surface of the material are called surface Rayleigh waves.

[0069] When using p-OCE to obtain detection signals for each position of a 3D-printed structure, MB scanning mode is used to maximize the imaging frame rate and obtain corresponding sub-detection signals at multiple moments. The p-OCE performs a set of hundreds of A-scans at each lateral position of the sample under test, analyzing the p-OCE signal changes at the same position and over time. During imaging, the p-OCE imaging unit and the piezoelectric excitation unit have synchronized trigger clocks. The sampling trigger clock signal of the p-OCE imaging unit simultaneously triggers the signal generator to output a sine wave signal. After amplification by the power amplifier, the sine wave signal drives the piezoelectric transducer to vibrate, stimulating the sample under test to produce elastic vibration. At each lateral position of the sample under test, a set of A-scan samples and a piezoelectric transducer vibration excitation are performed. Afterwards, the galvanometer moves the p-OCE scanning beam to the next lateral position and repeats the same scanning protocol until the scan area is fully sampled.

[0070] Step S306 : pre-processing the detection signal to obtain a structural-mechanical signal corresponding to each position of the printed structure.

[0071] The embodiment of the present invention also performs DC removal, wave number linear interpolation, and Fourier transform processing on the above-mentioned detection signals to obtain the structural-mechanical signal of the printed structure at each position. The structural-mechanical signal includes a phase signal and an amplitude signal. The amplitude signal can be processed to extract the geometric information of the printed structure, and the phase signal can be processed to obtain information such as the propagation speed of the elastic wave and the vibration displacement.

[0072] Among them, in order to use p-OCE to highly sensitively detect tiny vibrations in materials and realize the propagation imaging of weak amplitude elastic waves, a highly sensitive phase measurement method of p-OCE is required. The OCT complex signal corresponding to p-OCE includes phase value parameters and amplitude parameters, that is, the phase signal and amplitude signal mentioned above. After the detection signal corresponding to the collected elastic wave data is subjected to fast Fourier transform, the OCT complex signal including phase and amplitude at each spatial position will be obtained. Among them, (x, y, z) represents the spatial position of the sample, and t represents time.

[0073] Step S308: storing the phase value parameter and the amplitude parameter of each position as the process parameters of the printing structure corresponding to the second mechanical parameter.

[0074] Step S310 , determining vibration information corresponding to the printing structure at the current position according to the sub-detection signals and phase value parameters at multiple moments corresponding to each position in the process parameters.

[0075] In a specific implementation, the phase change corresponding to two adjacent moments at the current position is determined. Based on the phase change, the vibration velocity of the printed structure at each moment is calculated. Based on the vibration velocity, the vibration displacement corresponding to each moment is determined. A spatiotemporal displacement map is constructed based on the vibration displacement at each moment to obtain vibration information. The vibration information includes the vibration velocity and displacement of the printed structure.

[0076] Specifically, the embodiment of the present invention utilizes a phase-resolved Doppler method to obtain the phase change of the internal vibration of the material of the printed structure and calculate the vibration information inside the material, as shown in the following formula:

[0077]

[0078] Among them, V x,y,z,t is the vibration velocity of the material particle at the (x, y, z) position at time t, λ is the central wavelength of the swept light source, n is the refractive index of the medium, τ is the time interval, is the phase change of the OCT signal between two moments at the same location. The displacement of the (x, y, z) position inside the material from time t1 to time t2 can be expressed by the following formula:

[0079]

[0080] Step S312: determining the elastic frequency of the printing structure based on the vibration information.

[0081] Step S314 : determining the elastic wave velocity at each elastic frequency based on the elastic frequency, and drawing a wave velocity dispersion curve.

[0082] In the specific implementation, the spatiotemporal displacement map is subjected to a two-dimensional discrete Fourier transform to obtain a frequency-wavenumber domain map. The maximum frequency value is extracted from the frequency-wavenumber domain map and normalized to obtain an energy distribution curve. The target frequency corresponding to the highest energy point in the energy distribution curve is determined. Based on the frequency-wavenumber domain map, the ratio of the frequency corresponding to the target frequency value to the wavenumber domain is determined as the elastic wave velocity. The wave velocity dispersion curve is then plotted based on the elastic wave velocity at each frequency. The elastic wave velocity includes the shear wave propagation velocity and the Rayleigh wave propagation velocity.

[0083] Specifically, after measuring the vibration information in the material, the propagation of elastic waves in the material can be visualized and reconstructed by analyzing the vibration distribution within the material at different times. To analyze the propagation characteristics of the elastic waves, the Doppler phase image is Fourier transformed to analyze the propagation characteristics of the Doppler phase image, including its spectral distribution, energy distribution, and wave velocity dispersion curve. To obtain the dispersion characteristics of the elastic waves, the resulting space-time displacement image is subjected to a two-dimensional discrete Fourier transform, converting it from the time-space domain to the frequency-wavenumber domain, resulting in a corresponding frequency-wavenumber domain graph. In the frequency-wavenumber domain graph, the amplitude at each coordinate point represents the energy level. Then, by selecting the maximum value corresponding to each frequency along the frequency axis and performing normalization, a normalized energy distribution curve is generated, representing the distribution of elastic wave energy. The frequency corresponding to the highest energy point in the curve is the center frequency of the elastic wave. Based on the frequency-wavenumber domain graph, the ratio of the horizontal and vertical coordinates at the maximum amplitude point is calculated to obtain the elastic wave velocity at each frequency, ultimately resulting in the wave velocity dispersion curve.

[0084] Step S316 , calculating the second mechanical parameter corresponding to the printed structure according to the wave velocity dispersion curve.

[0085] When a sample is dynamically excited at a specific location using an external excitation source, the material generates tiny elastic vibrations at the excitation point. These elastic vibrations propagate from the excitation location into the surrounding medium within the sample or near the surface in the form of elastic waves. Depending on where the elastic waves propagate, different types of elastic waves can be generated in the material. Elastic waves propagating within thicker samples are called bulk waves, including compression waves and shear waves, while elastic waves propagating near the material's surface are called surface Rayleigh waves.

[0086] In a specific implementation, the second mechanical parameter is used to calculate the axial elastic modulus and the lateral elastic modulus. The second mechanical parameter includes the axial shear wave propagation velocity and the lateral shear wave propagation velocity of the printed structure, as well as the lateral Rayleigh wave propagation velocity, determined based on the wave velocity dispersion curve. Young's modulus and shear modulus are calculated based on the axial shear wave propagation velocity, the lateral shear wave propagation velocity, and the lateral Rayleigh wave propagation velocity. The axial elastic modulus and lateral elastic modulus of the printed material structure are obtained based on the Young's modulus and the shear modulus.

[0087] Specifically, the Young's modulus E is calculated according to the shear wave propagation velocity, E = 2ρ × (1 + v) × V S 2 , V SWhere Vs is the axial shear wave propagation velocity or the lateral shear wave propagation velocity. When Vs is the lateral shear wave propagation velocity, the lateral elastic modulus of the printed material structure is obtained according to the above formula; when Vs is the axial shear wave propagation velocity, the axial elastic modulus of the printed material structure is obtained according to the above formula. Where v is the Poisson's ratio of the material, and ρ is the material density. Under low strain conditions, the material can be considered incompressible, with a Poisson's ratio v of 0.5.

[0088] And, the lateral Young's modulus E near the sample surface is determined based on the Rayleigh wave propagation velocity. Rayleigh waves, as a common surface wave, appear within a depth range of approximately one wavelength on the surface of the material and propagate along the surface of the material. The relationship between Young's modulus and the surface Rayleigh wave propagation velocity can be given by the following formula: V R is the propagation velocity of Rayleigh waves, and the lateral Young's modulus near the surface of the printed material structure is obtained according to the above formula. Where ρ is the density of the material, v is the Poisson's ratio of the material, and V R is the Rayleigh wave propagation velocity. Measuring the Rayleigh wave propagation velocity on a material surface can be used to quantify the lateral Young's modulus near the surface of a printed material structure. When bio-inks cure slowly and are easily deformed, distortion can occur in bio-3D printed structures.

[0089] Another method for determining the mechanical property parameters of 3D-printed structures, provided by an embodiment of the present invention, integrates optical coherence (OCE) technology with a printing platform. OCE can penetrate 2-15 layers of a printed structure, depending on the material's scattering properties. Full-structure image reconstruction using p-OCE quantitatively characterizes the material deformation and properties of the printed structure by determining differences in structure, deformation, and viscoelasticity across the same layer at different times, providing feedback to control printing parameters. This method for monitoring the combined structural and mechanical parameters of the 3D printing process can rapidly acquire secondary mechanical property parameters, such as the axial and lateral elastic moduli, of the 3D-printed structure.

[0090] Furthermore, based on the above-mentioned device embodiment, an embodiment of the present invention also provides a structural-mechanical composite parameter monitoring device for a 3D printing process, wherein the device is configured in the above-mentioned method; the device includes an excitation module, a three-dimensional imaging detection module, and a signal processing module; the excitation module is used to generate an excitation signal when obtaining a process parameter corresponding to a second mechanical parameter, so as to cause the printed structure to generate an elastic wave; the three-dimensional imaging detection module is connected to the excitation module, and is used to emit imaging detection light according to the triggering operation of the excitation signal, and to obtain an imaging signal corresponding to the imaging detection light; the signal processing module is connected to the three-dimensional imaging detection module, and is used to process the imaging signal obtained by the three-dimensional imaging detection module, and extract the process parameter corresponding to the first mechanical parameter or the process parameter corresponding to the second mechanical parameter from the imaging signal to determine the mechanical characteristic parameters corresponding to the process parameter of the printed structure. The above-mentioned process parameters respectively include the structural-mechanical composite image of the corresponding printing process.

[0091] In its implementation, p-OCE stimulates the printed article to generate microvibrations through piezoelectric, ultrasonic, or jet excitation. These mechanical vibrations induce shear waves and surface waves that propagate in different directions within the printed article. The device uses a phase-sensitive OCE algorithm to detect and track the propagation of shear and surface waves within the tissue, quantitatively evaluating the secondary mechanical properties of the printed tissue based on viscoelastic creep modeling of the printed material. Phase-sensitive OCE can be implemented using swept-frequency optical coherence tomography (OCT). The swept-frequency laser source and signal processing module correspond to the aforementioned swept-frequency OCT technology.

[0092] Specifically, to simultaneously induce surface waves and shear waves in biomaterials, a coverslip is bonded to the bottom of the piezoelectric transducer as an excitation source. The top of the piezoelectric transducer is attached to a rigidly fixed glass plate, while the bottom coverslip is in close contact with the sample surface. A sine wave generated by a signal generator passes through an amplifier, driving the piezoelectric transducer to produce a tiny displacement, inducing elastic vibrations on the sample surface. The excitation module involves bonding a coverslip to the bottom of the piezoelectric transducer as an excitation source and generating a sine wave using a signal generator.

[0093] Figure 9 A schematic diagram of a structure-mechanical composite parameter monitoring device for a 3D printing process provided by an embodiment of the present invention is shown, which is a schematic diagram of the structure of a swept-frequency p-OCE structure-elasticity dual-modal imaging system; Figure 10 A schematic diagram of the integration of a p-OCE probe and a printing device is shown; Figure 11A schematic diagram of the operating principle of a device for monitoring the structural and mechanical parameters of a 3D printing process is shown. This schematic diagram illustrates the p-OCE structural-elastic dual-modal imaging principle. The top of the piezoelectric transducer, which comprises a ring-shaped PZT, is attached to a rigidly fixed glass plate. The cover glass at its bottom is in close contact with the sample surface. A sine wave generated by a signal generator passes through a PZT amplifier, driving the piezoelectric transducer to produce a tiny displacement, inducing elastic vibrations on the sample surface and generating elastic waves.

[0094] The 3D imaging detection module is based on a swept-frequency laser source. This source emits laser light that passes through a 99 / 1 splitting coupler and then splits it into two beams: one beam enters the reference arm, and the other enters the sample arm. The reference arm includes a fiber circulator, collimator, and focusing lens. The split beam entering the reference arm passes through the circulator, collimator, and focusing lens in sequence before being reflected by a plane mirror at the end of the reference arm. The reflected beam then returns along its original path back into the fiber. The sample arm includes a fiber circulator, scanning mirror, and scanning lens. The split beam entering the sample arm, after passing through the circulator, scanning mirror, and scanning lens, ultimately impinges on the sample at the end of the sample arm, where it is scattered by the sample's medium. The backscattered light from the sample is collected and returned to the optical path. The signal processing module interferometers the return beams from the two optical paths through a 50 / 50 splitting coupler. The interference signal is detected by a balanced detector and then transmitted to a computer for processing after analog-to-digital conversion to obtain the secondary mechanical parameters of the 3D-printed structure.

[0095] Furthermore, the structural-mechanical composite parameter monitoring device for a 3D printing process provided by an embodiment of the present invention has the same technical features as the structural-mechanical composite parameter monitoring method for a 3D printing process provided by the above embodiment, so it can also solve the same technical problems and achieve the same technical effects.

[0096] An embodiment of the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-mentioned Figures 1 to 8 The steps of the method are shown.

[0097] The embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. The computer program is executed by a processor. Figures 1 to 8 The steps of the method are shown.

[0098] The embodiment of the present invention also provides a structural diagram of an electronic device, such as Figure 12FIG. 6 is a schematic diagram of the structure of the electronic device, wherein the electronic device includes a processor 61 and a memory 60, the memory 60 stores computer executable instructions that can be executed by the processor 61, and the processor 61 executes the computer executable instructions to implement the above Figures 1 to 8 The method shown.

[0099] exist Figure 12 In the illustrated embodiment, the electronic device further includes a bus 62 and a communication interface 63 , wherein the processor 61 , the communication interface 63 and the memory 60 are connected via the bus 62 .

[0100] Among them, the memory 60 may include high-speed random access memory (RAM), and may also include non-volatile memory (non-volatile memory), such as at least one disk storage. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 63 (which can be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. can be used. The bus 62 can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc., and can also be an AMBA (Advanced Microcontroller Bus Architecture, on-chip bus standard) bus, wherein AMBA defines three types of buses, including APB (Advanced Peripheral Bus) bus, AHB (Advanced High-performance Bus) bus and AXI (Advanced eXtensible Interface) bus. The bus 62 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 12 Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0101] The processor 61 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits in the processor 61 or by software instructions. The processor 61 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of the present application may be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor 61 reads the information in the memory and combines its hardware to complete the above Figures 1 to 8 The method shown.

[0102] The computer program product of a method and device for determining structural-mechanical composite parameters of a 3D printing process provided in an embodiment of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the method described in the previous method embodiment. For specific implementation, please refer to the method embodiment and will not be repeated here.

[0103] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the system described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0104] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0105] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0106] Finally, it should be noted that the above embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above embodiments within the technical scope disclosed by the present invention, or replace some of the technical features therein with equivalents. Such modifications, changes or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for monitoring structural-mechanical composite parameters in a 3D printing process, characterized in that: The method is applied to a three-dimensional imaging detector connected to a 3D printing platform, and comprises: Obtaining process parameters of the 3D printing platform during the printing process using the three-dimensional imaging detector; the process parameters correspond to the printed structure; Inputting the process parameters into a pre-established calculation model, and calculating the mechanical characteristic parameters corresponding to the process parameters through the calculation model; The mechanical characteristic parameters include a first mechanical parameter and a second mechanical parameter; the process parameter corresponds to the first mechanical parameter or the second mechanical parameter; the first mechanical parameter is used to characterize the deformation characteristics corresponding to the material structure of the printed structure, and the second mechanical parameter is used to characterize the mechanical characteristics of the material structure of the printed structure related to vibration caused by external excitation; The three-dimensional imaging detector is integrated with a dynamic excitation source, which is controlled by timing to perform dynamic excitation operations on the printed structure during the 3D printing process; When the process parameter corresponds to the second mechanical parameter, the step of using the three-dimensional imaging detector to obtain the process parameter of the 3D printing platform during the printing process includes: Responding to dynamic excitation operations applied by the 3D printing platform when printing each section of the printed structure; measuring, by the three-dimensional imaging detector, a detection signal corresponding to each position of each section of the printed structure based on the dynamic excitation operation; Each section of the printing structure includes a multi-layer printing structure; the detection signal includes a vibration distribution corresponding to the elastic wave generated by the printing structure based on the dynamic excitation operation; Preprocessing the detection signal to obtain a structural-mechanical signal corresponding to each position of the printed structure; wherein the structural-mechanical signal includes a phase value parameter and an amplitude parameter; The phase value parameter and the amplitude parameter at each position are stored as process parameters of the printing structure corresponding to the second mechanical parameter.

2. The method according to claim 1, characterized in that When the process parameter corresponds to the first mechanical parameter, the step of using the three-dimensional imaging detector to obtain the process parameter of the 3D printing platform during the printing process includes: Acquiring a three-dimensional high-resolution image of the printed structure during printing using the three-dimensional imaging detector; Based on the three-dimensional high-resolution image, the parameter changes of the printed structure at different time points are quantified, and a time-dependent micro-deformation is established to obtain process parameters corresponding to the first mechanical parameters; wherein the process parameters include the squareness characteristics of the printed structure, and the squareness characteristics are determined based on the three-dimensional high-resolution image data.

3. The method according to claim 2, characterized in that The step of quantifying parameter changes of the printed structure at different time points based on the three-dimensional high-resolution image, establishing a time-dependent micro-deformation, and obtaining a process parameter corresponding to the first mechanical parameter includes: Acquire three-dimensional high-resolution image data of the printing layer of each section of the printing structure during the printing process; Based on the three-dimensional high-resolution image data, obtaining squareness characteristics of a channel cross section of each section of the printed structure; The squareness characteristic is stored as a process parameter of the first mechanical parameter.

4. The method according to claim 3, characterized in that The step of inputting the process parameters into a pre-established calculation model and calculating the mechanical characteristic parameters corresponding to the process parameters by using the calculation model includes: Determining an output result of the calculation model according to the squareness feature of each section of the printed structure in the process parameters and the time information corresponding to the three-dimensional high-resolution image data; The output result is compared with a preset comparison parameter, and a first mechanical parameter of the printed structure is determined based on the comparison result.

5. The method according to claim 4, characterized in that The pre-established calculation model includes: ； described Used to indicate the squareness characteristics of the channel cross section, It is used to indicate the multiplication of the diameter ratio of the upper and lower cross-section channels of each section of the printing structure during the printing process. is the ratio of the measured channel height of the printed structure to the preset layer height, is the preset floor height; The step of determining the output result of the calculation model based on the squareness feature of each section of the printed structure in the process parameters and the time information corresponding to the three-dimensional high-resolution image data includes: Determining, based on the squareness characteristics of each section of the printed structure and the time information corresponding to the three-dimensional high-resolution image data, a multiplication parameter of the ratio of the channel diameters of the upper and lower sections of the channel in each section of the structure and a squareness average value at the current moment; Determining the layer height cardinality corresponding to each section of the printing structure based on preset layer height parameters and layer height data of the printing structure; An output result of the calculation model is determined according to the squareness mean, the multiplication parameter and the floor height cardinality.

6. The method according to claim 1, characterized in that The detection signal is acquired through MB scanning mode, and the detection signal corresponds to sub-detection signals at multiple moments; The step of inputting the process parameters into a pre-established calculation model and calculating the mechanical characteristic parameters corresponding to the process parameters by using the calculation model includes: Determining vibration information corresponding to the printing structure at a current position according to the sub-detection signals at multiple moments corresponding to each position in the process parameters and the phase value parameter; Wherein, the vibration information includes the vibration speed and vibration displacement of the printing structure; determining an elastic frequency of the printing structure based on the vibration information; Based on the elastic frequency, determining the elastic wave velocity at each elastic frequency and drawing a wave velocity dispersion curve; Calculating a second mechanical parameter corresponding to the printed structure according to the wave velocity dispersion curve; The second mechanical parameter is used to calculate the axial elastic modulus and the lateral elastic modulus.

7. The method according to claim 6, characterized in that The step of determining vibration information corresponding to the printing structure at a current position according to the sub-detection signals at multiple moments corresponding to each position in the process parameters and the phase value parameter comprises: Based on the phase value parameters corresponding to two adjacent moments of the current position, determine the phase change corresponding to each moment; Calculating the vibration speed of the printing structure at each moment according to the phase change; The vibration displacement corresponding to each moment is determined according to the vibration speed, and a time-space displacement map is constructed based on the vibration displacement at each moment to obtain the vibration information.

8. The method according to claim 7, characterized in that The steps of determining the elastic frequency of the printing structure based on the vibration information; and determining the elastic wave velocity at each elastic frequency based on the elastic frequency, include: Performing a two-dimensional discrete Fourier transform on the space-time displacement map to obtain a frequency domain-wave number domain map; Extracting a maximum value of the frequency value from the frequency domain-wave number domain graph, and normalizing the maximum value to obtain an energy distribution curve; Determine a target frequency value corresponding to the highest energy point in the energy distribution curve; Based on the frequency domain-wave number domain diagram, the ratio of the frequency and wave number domain corresponding to the target frequency value is determined as the elastic wave velocity; the elastic wave velocity includes the shear wave propagation velocity and the Rayleigh wave propagation velocity.

9. A structural-mechanical composite parameter monitoring device for a 3D printing process, characterized in that: The device is configured as described in any one of claims 1 to 8; the device includes an excitation module, a three-dimensional imaging detection module and a signal processing module; The excitation module is used to generate an excitation signal when obtaining a process parameter corresponding to the second mechanical parameter, so as to enable the printed structure to generate an elastic wave; The three-dimensional imaging detection module is connected to the excitation module and is configured to emit imaging detection light according to a triggering operation of the excitation signal and obtain an imaging signal corresponding to the imaging detection light; The signal processing module is connected to the three-dimensional imaging detection module and is used to process the imaging signal acquired by the three-dimensional imaging detection module, extract the process parameter corresponding to the first mechanical parameter or the process parameter corresponding to the second mechanical parameter from the imaging signal, so as to determine the mechanical characteristic parameter of the printed structure corresponding to the process parameter; The step of extracting the process parameter corresponding to the second mechanical parameter from the imaging signal includes: Responding to dynamic excitation operations applied by the 3D printing platform when printing each section of the printed structure; Measuring, by a three-dimensional imaging detector, a detection signal corresponding to the dynamic excitation operation at each position of each section of the printed structure; wherein each section of the printed structure comprises a multi-layer printed structure; and the detection signal includes a vibration distribution corresponding to an elastic wave generated by the printed structure based on the dynamic excitation operation; Preprocessing the detection signal to obtain a structural-mechanical signal corresponding to each position of the printed structure; wherein the structural-mechanical signal includes a phase value parameter and an amplitude parameter; The phase value parameter and the amplitude parameter at each position are stored as process parameters of the printing structure corresponding to the second mechanical parameter.

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