Printing method and system for microfluidic apparatus, and computer-readable medium

Abstract

The present application mainly relates to the technical field of 3D printing, and specifically relates to a printing method and system for a microfluidic apparatus, and a computer-readable medium. The printing method comprises: performing first edge extraction processing on a preset exposure pattern, so as to obtain a first exposure pattern; performing second edge extraction processing on the preset exposure pattern, so as to obtain a second exposure pattern, wherein the second exposure pattern comprises a microfluidic channel; calculating a maximum principal stress of the microfluidic channel on the basis of performance parameters of a printing material; in response to the maximum principal stress being less than or equal to a preset threshold value, using the first exposure pattern to perform first exposure processing on the printing material, so as to obtain a first printed layer of a micro-channel apparatus; and using the second exposure pattern to perform second exposure processing on the first printed layer, so as to obtain a second printed layer. The present application can improve the printing forming precision and production efficiency of a microfluidic apparatus.

Description

Printing methods, systems and computer-readable media for microfluidic devices Technical Field

[0001] This application relates primarily to the field of 3D printing technology, and more specifically to a method, system, and computer-readable medium for printing a microchannel device. Background Technology

[0002] In the 3D printing process, the printing material solidifies in a specific area under the action of light, and is accumulated layer by layer according to the preset three-dimensional model, eventually building a complete 3D printed product.

[0003] Currently, products are typically printed using a full-width, multi-scale feature single-exposure method. However, when printing microfluidic devices with fine line features, such as microfluidic chips, existing printing methods make these tiny, enclosed fine line features prone to breakage, resulting in low printing accuracy. Once breakage occurs, the printed product will have defects or fail to form, thus reducing production efficiency. Summary of the Invention

[0004] The technical problem to be solved by this application is to provide a printing method, system and computer-readable medium for microfluidic devices, which can improve the printing accuracy and production efficiency of microfluidic devices.

[0005] The technical solution adopted in this application to solve the above-mentioned technical problems is a printing method for a microchannel device, comprising: performing a first edge extraction process on a preset exposure pattern to obtain a first exposure pattern; performing a second edge extraction process on the preset exposure pattern to obtain a second exposure pattern; wherein the second exposure pattern includes microchannels; calculating the maximum principal stress of the microchannels according to the performance parameters of the printing material; responding to the maximum principal stress being less than or equal to a preset threshold, performing a first exposure process on the printing material using the first exposure pattern to obtain a first printing area of ​​the microchannel device; and performing a second exposure process on the first printing area using the second exposure pattern to obtain a second printing area.

[0006] In one embodiment of this application, the calculation of the maximum principal stress of the microchannel based on the performance parameters of the printing material includes: calculating the curing volume shrinkage rate of the cured region of the printing material; calculating the transient pressure distribution of the uncured region of the printing material; constructing solid-liquid boundary conditions based on the curing volume shrinkage rate; calculating the pressure gradient based on the transient pressure distribution; simulating the stress distribution of the microchannel based on the solid-liquid boundary conditions and the pressure gradient, and calculating the maximum principal stress.

[0007] In one embodiment of this application, calculating the curing volume shrinkage rate of the cured region of the printed material includes: calculating the curing volume shrinkage rate using the following formula:

[0008] Where ε represents the curing volume shrinkage rate; ΔV represents the shrinkage volume of the printing material, ΔV<0; and V0 represents the initial curing area volume of the printing material.

[0009] In one embodiment of this application, calculating the transient pressure distribution in the uncured region of the printed material includes: constructing the Navier-Stokes equation for the printed material using the following formula:

[0010] Where ρ represents the density of the printing material; v represents the velocity field of the uncured liquid printing material; and t represents time. Let represent the gradient; p represent the transient pressure distribution; μ represent the viscosity of the printing material; f represent the external force field; solve the Navier-Stokes equations to obtain the transient pressure distribution p(x,y,t) of the uncured region; where (x,y) represents the coordinate position of the uncured region.

[0011] In one embodiment of this application, constructing solid-liquid boundary conditions based on the solidification volume shrinkage rate includes: constructing solid-liquid boundary conditions using the following formula:

[0012] Among them, v boundary Indicates the solid-liquid boundary condition; ε represents the solidification volume shrinkage rate; t cure This represents the curing time of the printing material; n represents the normal vector of the solid-liquid boundary.

[0013] In one embodiment of this application, calculating the pressure gradient based on the transient pressure distribution includes: calculating the pressure gradient using the following formula:

[0014] in, denoted by pressure gradient; (x, y) represents the coordinates of the uncured area; p represents the transient pressure distribution; i and j represent the spatial directions.

[0015] In one embodiment of this application, the maximum principal stress is calculated by simulating the stress distribution of the microchannel based on the solid-liquid boundary conditions and pressure gradient, including: calculating the maximum principal stress using the following formula:

[0016] Where, σ max σ0 represents the maximum principal stress; σ0 represents the initial stress generated by the curing shrinkage of the printing material. Indicates the pressure gradient; This represents the additional stress component caused by the pressure gradient.

[0017] In one embodiment of this application, the first edge extraction process and / or the second edge extraction process employ a width-first search algorithm; the first edge extraction process is performed on a preset exposure pattern to obtain a first exposure pattern, including: converting the preset exposure pattern into a binary image; traversing the pixels in the binary image using a width-first search function; in response to the current pixel being an edge pixel, marking the current pixel as an edge, and continuing to traverse the adjacent pixels of the current pixel; in response to traversing all pixels in the binary image, connecting the edges and outputting the first exposure pattern.

[0018] To address the aforementioned technical problems, this application also proposes a microfluidic device printing system, comprising: a memory for storing instructions executable by a processor; and a processor for executing the instructions to implement the microfluidic device printing method described above.

[0019] To address the aforementioned technical problems, this application also proposes a computer-readable medium storing computer program code, which, when executed by a processor, implements the above-described method for printing a microfluidic device.

[0020] The technical solution of this application avoids the risk of breakage in the fine line area of ​​the microchannel device by pre-calculating the maximum principal stress of the microchannel and performing exposure processing only when the maximum principal stress meets the condition. This application performs first edge extraction processing and second edge extraction processing on the full-area exposure pattern, and divides the printing process into two exposures. The first exposure exposes a large area of ​​the internal region, so that the internal pre-curing shrinkage occurs; the second exposure exposes the microchannel with the fine line area, so that the fine line structure and outer contour can be formed completely and accurately.

[0021] This application enables the simultaneous forming of large-scale features across the entire surface of a microfluidic device while ensuring that small-scale fine-line features remain unbroken, and avoids seam defects and dark area exposure caused by splicing. This improves the printing accuracy and production efficiency of the microfluidic device. This application can be applied to improve the projection forming accuracy of full-scale, multi-scale microfluidic feature surfaces in sub-pixel micro-scanning 3D printing.

[0022] Overview of the attached figures

[0023] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings, wherein:

[0024] Figure 1 is an exemplary flowchart of a microchannel device printing method according to an embodiment of this application;

[0025] Figure 2 is a schematic diagram of a full-frame exposure pattern in one embodiment of this application;

[0026] Figure 3 is a schematic diagram of the first exposure pattern in one embodiment of this application;

[0027] Figure 4 is a schematic diagram of the second exposure pattern in one embodiment of this application;

[0028] Figure 5 is a schematic diagram of small-sized fine line feature defects produced by the traditional single-exposure process;

[0029] Figure 6 is a schematic diagram of small-sized fine line features produced using the printing method of this application;

[0030] Figure 7 is a system block diagram of a printing system for a microfluidic device according to an embodiment of this application.

[0031] Preferred embodiments of this application

[0032] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0033] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein, and therefore this application is not limited to the specific embodiments disclosed below.

[0034] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0035] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0036] This application proposes a method for printing a microfluidic device, which can be applied to subpixel micro-scanning 3D printing scenarios. The microfluidic device printing method of this application can run in a subpixel micro-scanning full-frame projection 3D printer, for example, within the printer's controller, or it can run on a cloud platform. When the microfluidic device printing method runs on a cloud platform, data from the printer and data from the cloud platform interact via a wireless network. Exemplarily, the cloud platform may include a private cloud, public cloud, hybrid cloud, community cloud, distributed cloud, interconnected cloud, and multiple clouds, or any combination thereof. This application does not limit the operating environment of the microfluidic device printing method.

[0037] Figure 1 is an exemplary flowchart of a microchannel device printing method according to an embodiment of this application. Referring to Figure 1, the microchannel device printing method of this embodiment includes the following steps:

[0038] Step S110: Perform first edge extraction processing on the preset exposure pattern to obtain the first exposure pattern.

[0039] Step S120: Perform a second edge extraction process on the preset exposure pattern to obtain a second exposure pattern; wherein the second exposure pattern includes microchannels.

[0040] Step S130: Calculate the maximum principal stress of the microchannel based on the performance parameters of the printing material.

[0041] Step S140: In response to the maximum principal stress being less than or equal to a preset threshold, the printing material is subjected to a first exposure process using a first exposure pattern to obtain a first printing area for the microchannel device.

[0042] Step S150: Perform a second exposure process on the first printing area using the second exposure pattern to obtain a second printing area.

[0043] For example, the microfluidic device mentioned in this application may be a microfluidic chip, and the printing material may be a photosensitive resin. This application does not limit the type of microfluidic device and printing material.

[0044] The following details steps S110 to S150 described above:

[0045] In step S110, the preset exposure pattern is subjected to a first edge extraction process to obtain a first exposure pattern.

[0046] Figure 2 is a schematic diagram of a full-area exposure pattern in one embodiment of this application, and Figure 3 is a schematic diagram of a first exposure pattern in one embodiment of this application. Exemplarily, the preset exposure pattern mentioned in this application can be the pattern shown in Figure 2. After performing a first edge extraction process on the preset exposure pattern 200, the first exposure pattern 300 shown in Figure 3 is obtained. The white area in the first exposure pattern 300 is the area to be exposed. Subsequently, the first exposure pattern 300 can be used to expose a large area, causing the printing material to pre-cur and shrink internally.

[0047] In some embodiments, the first edge extraction process employs a width-first search algorithm. Performing the first edge extraction process on a preset exposure pattern to obtain a first exposure pattern includes:

[0048] Step S1101: Convert the preset exposure pattern into a binary image.

[0049] Step S1102: Use a breadth-first search function to traverse the pixels in the binary image.

[0050] Step S1103: In response to the current pixel being an edge pixel, mark the current pixel as an edge and continue traversing the adjacent pixels of the current pixel.

[0051] Step S1104: In response to traversing all pixels in the binary image, connect the edges and output the first exposure pattern.

[0052] For example, this application employs a breadth-first search algorithm to perform edge extraction processing on the full-frame exposure pattern. Specifically, the method involves converting the preset exposure pattern into a suitable format (such as a binary image), defining a BFS (Breadth First Search) function to traverse each pixel in the image. The BFS function checks whether the current pixel is an edge pixel; if so, it is marked as an edge, and all its unvisited neighboring pixels are accessed. Finally, after traversing the entire image, all connected edge pixels are identified and marked, thereby generating an exposure pattern (such as the first and second exposure patterns described in this application), which highlights the edge features in the image.

[0053] In step S120, a second edge extraction process is performed on the preset exposure pattern to obtain a second exposure pattern; wherein the second exposure pattern includes microchannels. In some embodiments, the second edge extraction process employs a width-first search algorithm.

[0054] Figure 4 is a schematic diagram of the second exposure pattern in one embodiment of this application. Exemplarily, the second exposure pattern in this application can be the pattern shown in Figure 4, where the second exposure pattern 400 includes small-sized fine line features, i.e., microchannels, the width of which does not exceed 50 μm (micrometers). Some of the larger features in the first exposure pattern 300 have a surface area not exceeding 100 mm (millimeters). When performing edge extraction processing on the preset exposure pattern 200, different BFS functions can be defined to obtain the first exposure pattern 300 and the second exposure pattern 400.

[0055] In step S130, the maximum principal stress of the microchannel is calculated based on the performance parameters of the printing material. For example, in traditional printing methods, full-width multi-scale features are typically exposed only once, which may lead to the easy breakage of fine lines in small, closed features. This phenomenon is not significantly related to exposure time, light intensity, or interlayer waiting time. The main reason for the easy breakage of fine lines is that the printing material (such as photosensitive resin) undergoes volume shrinkage during curing, causing a pressure gradient to form in the resin of non-exposed areas. When the pressure gradient at the location of the fine line structure exceeds its fracture threshold, a breakage phenomenon occurs, resulting in defects or molding failure.

[0056] Based on the aforementioned factors that may lead to breakage of the fine lines, and considering the need to determine whether exposure process parameters will cause the fine line structure to break under a fixed fine line width, this application proposes a solid-liquid coupling model based on the finite element method. This model, combined with the solid-liquid boundary movement caused by volume shrinkage during resin curing, numerically simulates the transient pressure distribution within the uncured region, calculates the maximum principal stress of the microchannel, and thus quantitatively assesses the pressure gradient and breakage risk in the fine line region.

[0057] In some embodiments, calculating the maximum principal stress of the microchannel based on the performance parameters of the printing material includes:

[0058] Step S1301: Calculate the curing volume shrinkage rate of the cured area of ​​the printed material.

[0059] Step S1302: Calculate the transient pressure distribution in the uncured area of ​​the printed material.

[0060] Step S1303: Construct solid-liquid boundary conditions based on the solidification volume shrinkage rate.

[0061] Step S1304: Calculate the pressure gradient based on the transient pressure distribution.

[0062] Step S1305: Simulate the stress distribution of the microchannel based on the solid-liquid boundary conditions and pressure gradient, and calculate the maximum principal stress.

[0063] For example, the stress distribution of the microchannel can be simulated and its maximum principal stress can be determined through the above steps S1301 to S1305. Subsequently, the fracture risk of the fine line region can be quantitatively assessed based on the maximum principal stress.

[0064] In some embodiments, for step S1301, calculating the curing volume shrinkage rate of the cured area of ​​the printed material includes: calculating the curing volume shrinkage rate using the following formula (1):

[0065] Where ε represents the curing volume shrinkage rate; ΔV represents the shrinkage volume of the printing material, ΔV<0; and V0 represents the initial cured region volume of the printing material. For example, step S1301 above is equivalent to modeling the cured region. The cured region can be considered as a linear elastic material, and its volume shrinkage during the curing process may cause transient movement of the solid-liquid boundary. This boundary will constrain the uncured liquid resin, resulting in fluid flow and pressure changes.

[0066] In some embodiments, for step S1302, calculating the transient pressure distribution in the uncured area of ​​the printed material includes:

[0067] Step S1302A: Construct the Navier-Stokes equations for the printing material using the following formulas (2) and (3):

[0068] Where ρ represents the density of the printing material; v represents the velocity field of the uncured liquid printing material; and t represents time. denoted by gradient; p represents transient pressure distribution; μ represents the viscosity of the printing material; f represents the external force field.

[0069] Step S1302B: Solve the Navier-Stokes equations to obtain the transient pressure distribution p(x,y,t) of the uncured region; where (x,y) represents the coordinate position of the uncured region.

[0070] For example, step S1302A above is equivalent to modeling the uncured region. The uncured region can be regarded as a laminar incompressible fluid, and its internal pressure distribution follows the Navier-Stokes equations. This application can obtain the transient pressure distribution by solving the Navier-Stokes equations.

[0071] In some embodiments, for step S1303, constructing solid-liquid boundary conditions based on the solidification volume shrinkage rate includes: constructing solid-liquid boundary conditions using the following formula (4):

[0072] Among them, v boundary Indicates the solid-liquid boundary condition; ε represents the solidification volume shrinkage rate; t cure This represents the curing time of the printing material; n represents the normal vector of the solid-liquid boundary. For example, the solid-liquid interface can serve as a moving boundary, the speed of which is proportional to the volume shrinkage rate during curing.

[0073] In some embodiments, for step S1304, calculating the pressure gradient based on the transient pressure distribution includes: calculating the pressure gradient using the following formula (5):

[0074] in, Let (x, y) represent the pressure gradient; (x, y) represent the coordinates of the unsolidified region; p represent the transient pressure distribution; and i and j represent the spatial directions. For example, the transient pressure distribution p(x, y, t) of the fluid can be obtained by solving the formula (2) mentioned above.

[0075] In some embodiments, for step S1305, the maximum principal stress is calculated based on the stress distribution of the microchannel simulated according to the solid-liquid boundary conditions and pressure gradient, including: calculating the maximum principal stress using the following formula (6):

[0076] Where, σ max σ represents the maximum principal stress in the microchannel (i.e., the fine-line region); σ0 represents the initial stress generated by the curing shrinkage of the printing material. Indicates the pressure gradient; This represents the additional stress component caused by the pressure gradient. For example, under solid-liquid coupling, the stress distribution of a thin wire structure may be affected by the pressure gradient, so the maximum principal stress can be calculated using the above formula (6).

[0077] In step S140, in response to the maximum principal stress being less than or equal to a preset threshold, the printing material is subjected to a first exposure process using a first exposure pattern to obtain a first printing area for the microchannel device.

[0078] For example, the preset threshold is, for instance, the tensile strength σ of the printing material (such as photosensitive resin). c It can be based on the fracture strength σ c This is used to determine whether the thin thread structure has broken. If σ max ≤σ c If the thin-wire structure does not have a risk of breakage; max >σ c If the fine line structure is found to be at risk of breakage, the exposure strategy can be optimized (such as adjusting the exposure order of the zones or edge extraction processing) to reduce the pressure gradient in the uncured area, ensure the complete formation of the fine line structure, and improve printing stability and forming accuracy.

[0079] For example, the threshold judgment in steps S130 and S140 mentioned above is equivalent to a numerical simulation process, which will be summarized and explained here.

[0080] (1) Performance parameters of printing materials (such as photosensitive resin): resin density ρ, viscosity μ, elastic modulus E, curing volume shrinkage ε, curing time t cure Fracture strength σ c Parameters such as these.

[0081] (2) Model establishment: Based on the finite element method, a solid-liquid coupling model is constructed, and the initial boundary conditions of the solidified region and the initial boundary conditions and moving boundary conditions of the unsolidified region are set.

[0082] (3) Transient solution: Solve the Navier-Stokes equations to obtain the transient pressure distribution p(x,y,t) in the uncured region.

[0083] (4) Pressure gradient calculation: Based on the transient pressure distribution, calculate the pressure gradient inside the uncured area.

[0084] (5) Stress distribution analysis: Apply pressure gradient and boundary conditions to simulate the stress distribution in the thin wire region and calculate the maximum principal stress σ. max .

[0085] (6) Fracture determination: The maximum principal stress σ max With resin tensile strength σ c By comparing the two structures, we can determine whether there is a risk of breakage in the thin-wire structure.

[0086] This application uses numerical simulation to accurately assess the risk of fine wire breakage under exposure process parameters and determine whether given conditions are suitable for the 3D printing process of microchannel devices.

[0087] In step S150, the first printing area is subjected to a second exposure process using the second exposure pattern to obtain a second printing area. Exemplarily, this application employs two exposures: the first exposure exposes the internal region, and the second exposure exposes the outer contour. Figure 5 is a schematic diagram of small-sized fine line feature defects produced by a conventional single-exposure process, and Figure 6 is a schematic diagram of small-sized fine line features produced using the printing method of this application. Comparing Figures 5 and 6, it can be seen that the fine line features of this application are clearer and more rounded in image 600 of the printed area and image 500 of the conventionally printed area. In practical applications, the printing area can be divided into multiple independent small regions and printed by splicing exposures multiple times; this application does not limit whether splicing exposures are used.

[0088] The technical solution of this application avoids the risk of breakage in the fine line area of ​​the microchannel device by pre-calculating the maximum principal stress of the microchannel and performing exposure processing only when the maximum principal stress meets the condition. This application performs first edge extraction processing and second edge extraction processing on the full-area exposure pattern, and divides the printing process into two exposures. The first exposure exposes a large area of ​​the internal region, so that the internal pre-curing shrinkage occurs; the second exposure exposes the microchannel with the fine line area, so that the fine line structure and outer contour can be formed completely and accurately.

[0089] This application enables the simultaneous forming of large-scale features across the entire surface of a microfluidic device while ensuring that small-scale fine-line features remain unbroken, and avoids seam defects and dark area exposure caused by splicing. This improves the printing accuracy and production efficiency of the microfluidic device. This application can be applied to improve the projection forming accuracy of full-scale, multi-scale microfluidic feature surfaces in sub-pixel micro-scanning 3D printing.

[0090] This application also includes a microfluidic device printing system, comprising a memory and a processor. The memory stores instructions executable by the processor; the processor executes the instructions to implement the microfluidic device printing method described above.

[0091] Figure 7 is a system block diagram of a printing system for a microfluidic device according to an embodiment of this application. Referring to Figure 7, the printing system 700 of the microfluidic device may include an internal communication bus 701, a processor 702, a read-only memory (ROM) 703, a random access memory (RAM) 704, and a communication port 705. The printing system 700 of the microfluidic device may also include a hard disk 706. The internal communication bus 701 enables data communication between the components of the printing system 700 of the microfluidic device. The processor 702 can perform judgments and issue prompts. In some embodiments, the processor 702 may consist of one or more processors. The communication port 705 enables data communication between the printing system 700 of the microfluidic device and external devices. In some embodiments, the printing system 700 of the microfluidic device can send and receive information and data from a network through the communication port 705. The printing system 700 of this microfluidic device may also include different types of program storage units and data storage units, such as a hard disk 706, a read-only memory (ROM) 703, and a random access memory (RAM) 704, capable of storing various data files used for computer processing and / or communication, as well as possible program instructions executed by the processor 702. The processor executes these instructions to implement the main part of the method. The results of the processor processing are transmitted to the user equipment via a communication port and displayed on the user interface.

[0092] The above-described microfluidic device printing method can be implemented as a computer program, stored in hard disk 706, and loaded into processor 702 for execution to implement the microfluidic device printing method of this application.

[0093] This application also includes a computer-readable medium storing computer program code that, when executed by a processor, implements the printing method of the microchannel device described above.

[0094] When the microfluidic device printing method is implemented as a computer program, it can also be stored as an article of manufacture in a computer-readable storage medium. For example, computer-readable storage media can include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic stripes), optical discs (e.g., compact discs (CDs), digital multifunction discs (DVDs)), smart cards, and flash memory devices (e.g., electrically erasable programmable read-only memory (EPROM), cards, sticks, key drives). Furthermore, the various storage media described herein can represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" can include, but is not limited to, wireless channels and various other media (and / or storage media) capable of storing, containing, and / or carrying code and / or instructions and / or data.

[0095] It should be understood that the embodiments described above are merely illustrative. The embodiments described herein may be implemented in hardware, software, firmware, middleware, microcode, or any combination thereof. For hardware implementation, the processor may be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and / or other electronic units designed to perform the functions described herein, or combinations thereof.

[0096] Some aspects of this application can be executed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The aforementioned hardware or software may be referred to as a "data block," "module," "engine," "unit," "component," or "system." The processor may be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or combinations thereof. Furthermore, aspects of this application may manifest as computer products residing in one or more computer-readable media, including computer-readable program code. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic tapes, etc.), optical discs (e.g., compressed CDs, digital multifunction DVDs, etc.), smart cards, and flash memory devices (e.g., cards, sticks, key drives, etc.).

[0097] A computer-readable medium may contain a propagated data signal containing computer program code, for example, on baseband or as part of a carrier wave. This propagated signal may take various forms, including electromagnetic, optical, and so on, or suitable combinations thereof. A computer-readable medium can be any computer-readable medium other than a computer-readable storage medium, which can be connected to an instruction execution system, apparatus, or device to enable communication, propagation, or transmission of a program for use. The program code located on the computer-readable medium can be propagated through any suitable medium, including radio, cable, fiber optic cable, radio frequency signals, or similar media, or any combination of the above media.

[0098] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0099] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0100] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

Claims

1. A method for printing a microfluidic device, characterized in that, include: The preset exposure pattern is subjected to a first edge extraction process to obtain the first exposure pattern; The preset exposure pattern is subjected to a second edge extraction process to obtain a second exposure pattern; wherein, the second exposure pattern includes microchannels; The maximum principal stress of the microchannel is calculated based on the performance parameters of the printing material. In response to the maximum principal stress being less than or equal to a preset threshold, the printing material is subjected to a first exposure process using the first exposure pattern to obtain a first printing area of ​​the microchannel device. The first printable surface is subjected to a second exposure process using the second exposure pattern to obtain a second printable surface.

2. The printing method as described in claim 1, characterized in that, The maximum principal stress of the microchannel is calculated based on the performance parameters of the printing material, including: Calculate the curing volume shrinkage rate of the cured region of the printed material; Calculate the transient pressure distribution in the uncured area of ​​the printed material; Construct solid-liquid boundary conditions based on the solidification volume shrinkage rate; Calculate the pressure gradient based on the transient pressure distribution; The maximum principal stress is calculated by simulating the stress distribution of the microchannel based on the solid-liquid boundary conditions and the pressure gradient.

3. The printing method as described in claim 2, characterized in that, Calculating the curing volume shrinkage rate of the cured region of the printed material includes: calculating the curing volume shrinkage rate using the following formula: Wherein, ε represents the curing volume shrinkage rate; ΔV represents the shrinkage volume of the printing material, ΔV<0; V0 represents the initial curing region volume of the printing material.

4. The printing method as described in claim 2, characterized in that, Calculate the transient pressure distribution in the uncured area of ​​the printed material, including: The Navier-Stokes equations for the printing material are constructed using the following formula: Wherein, ρ represents the density of the printing material; v represents the velocity field of the uncured liquid in the printing material; and t represents time. The gradient is represented by p; the transient pressure distribution is represented by μ; the viscosity of the printing material is represented by μ; and the external force field is represented by f. Solve the Navier-Stokes equations to obtain the transient pressure distribution p(x,y,t) of the uncured region; where (x,y) represents the coordinate position of the uncured region.

5. The printing method as described in claim 2, characterized in that, Constructing solid-liquid boundary conditions based on the solidification volume shrinkage rate includes: constructing the solid-liquid boundary conditions using the following formula: Among them, v boundary The solid-liquid boundary condition is represented by ε; the solidification volume shrinkage rate is represented by t. cure The curing time of the printed material is represented by ; n represents the normal vector of the solid-liquid boundary.

6. The printing method as described in claim 2, characterized in that, Calculating the pressure gradient based on the transient pressure distribution includes: calculating the pressure gradient using the following formula: in, The pressure gradient is represented by (x, y); the coordinates of the uncured area are represented by (x, y); p represents the transient pressure distribution; and i and j represent the spatial directions.

7. The printing method according to any one of claims 2-6, characterized in that, Based on the solid-liquid boundary conditions and the pressure gradient, the stress distribution of the microchannel is simulated, and the maximum principal stress is calculated, including: calculating the maximum principal stress using the following formula: Where, σ max The maximum principal stress is represented by σ0; σ0 represents the initial stress generated by the curing shrinkage of the printing material. This represents the pressure gradient; This represents the additional stress component caused by the pressure gradient.

8. The printing method as described in claim 1, characterized in that, The first edge extraction process and / or the second edge extraction process employ a width-first search algorithm; The preset exposure pattern is subjected to a first edge extraction process to obtain a first exposure pattern, including: Convert the preset exposure pattern into a binary image; The pixels in the binary image are traversed using a breadth-first search function; In response to the current pixel being an edge pixel, the current pixel is marked as an edge, and the process continues to traverse the adjacent pixels of the current pixel; In response to traversing all pixels in the binary image, the edges are connected and the first exposure pattern is output.

9. A printing system for a microfluidic device, characterized in that, include: Memory is used to store instructions executed by the processor; A processor for executing the instructions to implement the printing method of the microchannel device as described in any one of claims 1-8.

10. A computer-readable medium storing computer program code, characterized in that, The computer program code, when executed by a processor, implements the printing method of the microchannel device as described in any one of claims 1-8.

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