Printing method, system and computer readable medium of microfluidic device

Abstract

The present invention mainly relates to the field of 3D printing technology, and specifically relates to a printing method, system and computer-readable medium for a microfluidic device, the printing method 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 a microfluidic channel; calculating the maximum principal stress of the microfluidic channel according to the performance parameters of the printing material; in response 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 format of the microfluidic device; performing a second exposure process on the first printing format using the second exposure pattern to obtain a second printing format. The present invention can improve the printing molding accuracy and production efficiency of the microfluidic device.

Description

Technical Field

[0001] The present invention mainly relates to the field of 3D printing technology, and in particular to a printing method, system and computer-readable medium for a microfluidic device. Background Art

[0002] During the 3D printing process, the printing material solidifies in specific areas under the action of light, accumulates layer by layer according to the preset three-dimensional model, and finally builds a complete 3D printed product.

[0003] At present, the printing method of full-format multi-scale features in one exposure is usually adopted to print products. If microfluidic devices with fine line features are to be printed, such as microfluidic chips, the existing printing method makes it easy for small and closed fine line features to break, and there is a problem of low printing precision. Once a break occurs, the printed product will have defects or molding failure, thereby reducing production efficiency. Summary of the invention

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

[0005] The technical solution adopted by the present application to solve the above-mentioned technical problems is a printing method for a microfluidic 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 a microfluidic channel; calculating the maximum principal stress of the microfluidic channel according to the performance parameters of the printed material; in response to the maximum principal stress being less than or equal to a preset threshold, performing a first exposure process on the printed material using the first exposure pattern to obtain a first printed format of the microfluidic device; performing a second exposure process on the first printed format using the second exposure pattern to obtain a second printed format.

[0006] In one embodiment of the present application, the maximum principal stress of the microfluidic channel is calculated based on the performance parameters of the printed material, including: calculating the solidification volume shrinkage rate of the solidified area of ​​the printed material; calculating the transient pressure distribution of the uncured area of ​​the printed material; constructing the solid-liquid boundary condition based on the solidification volume shrinkage rate; calculating the pressure gradient based on the transient pressure distribution; simulating the stress distribution of the microfluidic channel based on the solid-liquid boundary condition and the pressure gradient, and calculating the maximum principal stress.

[0007] In one embodiment of the present application, calculating the curing volume shrinkage rate of the curing area of ​​the printing material includes: calculating the curing volume shrinkage rate using the following formula:

[0008]

[0009] in, Indicates the volume shrinkage rate of curing; Indicates the shrinkage volume of the printed material. ; Represents the initial solidified area volume of the printed material.

[0010] In one embodiment of the present application, calculating the transient pressure distribution of the uncured area of ​​the printed material includes: constructing the Navier Stokes equation of the printed material using the following formula:

[0011]

[0012]

[0013] in, Indicates the density of the printed material; Represents the velocity field of the uncured liquid of the printing material; Indicates time; represents the gradient; represents the transient pressure distribution; Indicates the viscosity of the printing material; Represents the external force field; solves the Navier-Stokes equations to obtain the transient pressure distribution in the uncured area ;in, Indicates the coordinate position of the uncured area.

[0014] In one embodiment of the present application, constructing a solid-liquid boundary condition according to the solidification volume shrinkage rate includes: constructing the solid-liquid boundary condition using the following formula:

[0015]

[0016] in, represents the solid-liquid boundary condition; Indicates the volume shrinkage rate of curing; Indicates the curing time of the printed material; Represents the normal vector of the solid-liquid boundary.

[0017] In one embodiment of the present application, calculating the pressure gradient according to the transient pressure distribution includes: calculating the pressure gradient using the following formula:

[0018]

[0019] in, represents the pressure gradient; Indicates the coordinate position of the uncured area; represents the transient pressure distribution; , Indicates spatial direction.

[0020] In one embodiment of the present application, the stress distribution of the microchannel is simulated according to the solid-liquid boundary condition and the pressure gradient, and the maximum principal stress is calculated, including: calculating the maximum principal stress using the following formula:

[0021]

[0022] in, represents the maximum principal stress; Indicates the initial stress caused by the curing shrinkage of the printed material; represents the pressure gradient; Represents the additional stress component caused by the pressure gradient.

[0023] In one embodiment of the present application, the first edge extraction processing and / or the second edge extraction processing adopts a width-first search algorithm; the first edge extraction processing 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.

[0024] To solve the above technical problems, the present application also proposes a printing system for a microfluidic device, comprising: a memory for storing instructions executable by a processor; and a processor for executing the instructions to implement the above printing method for the microfluidic device.

[0025] In order to solve the above technical problems, the present application also proposes a computer-readable medium storing a computer program code, and the computer program code implements the above printing method for the microfluidic device when executed by a processor.

[0026] The technical solution of the present application can avoid the risk of breakage in the fine line area of ​​the microfluidic device by pre-calculating the maximum principal stress of the microfluidic channel and performing exposure processing only when the maximum principal stress meets the conditions; the present application performs a first edge extraction processing and a second edge extraction processing on the full-format exposure pattern, and divides the printing process into two exposures, the first exposing a large area of ​​the internal area to allow the interior to be pre-cured and shrunk; the second exposing the microfluidic channel with a fine line area allows the fine line structure and the outer contour to be completely and accurately formed.

[0027] The present application can ensure that small-sized fine-line features are not broken while forming large-scale features of the full-format microfluidic device, and will not produce seam defects caused by splicing and dark area exposure, which can improve the printing precision and production efficiency of the microfluidic device. The present application can be used to improve the projection molding precision of full-format multi-scale microfluidic feature surfaces in sub-pixel micro-scanning 3D printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings, wherein:

[0029] Figure 1 is an exemplary flow chart of a printing method of a microfluidic device according to an embodiment of the present application;

[0030] Figure 2 is a schematic diagram of a full-width exposure pattern in an embodiment of the present application;

[0031] Figure 3 is a schematic diagram of a first exposure pattern in an embodiment of the present application;

[0032] Figure 4 is a schematic diagram of a second exposure pattern in one embodiment of the present application;

[0033] Figure 5 This is a schematic diagram of small-size fine-line feature defects produced by the traditional single-exposure process;

[0034] Figure 6 is a schematic diagram of a small-size fine line feature produced by the printing method of the present application;

[0035] Figure 7 4 is a system block diagram of a printing system for a microfluidic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and therefore the present application is not limited to the specific embodiments disclosed below.

[0038] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0039] Flowcharts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0040] The present application proposes a printing method for a microfluidic device, which can be applied to sub-pixel micro-scanning 3D printing scenarios. The printing method for a microfluidic device of the present application can be run in a sub-pixel micro-scanning full-format projection 3D printer, for example, in the controller of the printer, and can also be run in a cloud platform. When the printing method for the microfluidic device is run on a cloud platform, the data on the printer side interacts with the cloud platform data through a wireless network. Exemplarily, the cloud platform may include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, an interconnected cloud, and multiple clouds, or any combination thereof. The present application does not limit the operating environment of the printing method for the microfluidic device.

[0041] Figure 1 is an exemplary flow chart of a printing method of a microfluidic device according to an embodiment of the present application, with reference to Figure 1 As shown, the printing method of the microfluidic device of this embodiment includes the following steps:

[0042] Step S110: performing a first edge extraction process on the preset exposure pattern to obtain a first exposure pattern.

[0043] Step S120: performing a second edge extraction process on the preset exposure pattern to obtain a second exposure pattern; wherein the second exposure pattern includes a microchannel.

[0044] Step S130: Calculate the maximum principal stress of the microchannel according to the performance parameters of the printing material.

[0045] Step S140: in response to the maximum principal stress being less than or equal to a preset threshold, performing a first exposure process on the printing material using a first exposure pattern to obtain a first printing format of the microfluidic channel device.

[0046] Step S150: performing a second exposure process on the first printing format using a second exposure pattern to obtain a second printing format.

[0047] Exemplarily, the microfluidic device mentioned in the present application may be a microfluidic chip, and the printing material may be a photosensitive resin. The present application does not limit the types of the microfluidic device and the printing material.

[0048] The above steps S110 to S150 are described in detail below:

[0049] In step S110, a first edge extraction process is performed on the preset exposure pattern to obtain a first exposure pattern.

[0050] Figure 2 is a schematic diagram of a full-width exposure pattern in an embodiment of the present application, Figure 3 is a schematic diagram of a first exposure pattern in an embodiment of the present application. For example, the preset exposure pattern referred to in the present application may be Figure 2 After performing the first edge extraction process on the preset exposure pattern 200, the obtained Figure 3 The first exposure pattern 300 is shown. The white area in the first exposure pattern 300 is the area that needs to be exposed. The first exposure pattern 300 can be used to expose a large area later, so that the inside of the printed material is pre-cured and shrunk.

[0051] In some embodiments, the first edge extraction process uses a width-first search algorithm. Performing the first edge extraction process on the preset exposure pattern to obtain the first exposure pattern includes:

[0052] Step S1101: converting a preset exposure pattern into a binary image.

[0053] Step S1102: traverse the pixels in the binary image using a breadth-first search function.

[0054] Step S1103: In response to the current pixel being an edge pixel, the current pixel is marked as an edge, and the adjacent pixels of the current pixel are continuously traversed.

[0055] Step S1104: in response to traversing all pixels in the binary image, connecting edges and outputting a first exposure pattern.

[0056] Exemplarily, the present application uses a breadth-first search algorithm to perform edge extraction processing on the full-frame exposure pattern. The specific implementation method is, for example: converting the preset exposure pattern into a format suitable for processing (such as a binary image), and 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 marks it as an edge and accesses all its unvisited adjacent pixels. Finally, the entire image is traversed, and all connected edge pixels are identified and marked, thereby generating an exposure pattern (such as the first exposure pattern and the second exposure pattern mentioned in the present application), which highlights the edge features in the image.

[0057] 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 a microchannel. In some embodiments, the second edge extraction process uses a breadth-first search algorithm.

[0058] Figure 4 is a schematic diagram of a second exposure pattern in an embodiment of the present application. For example, the second exposure pattern referred to in the present application may be Figure 4In the pattern shown, the second exposure pattern 400 includes small-sized fine line features, namely, microchannels, and the width of these small-sized fine line features does not exceed 50 μm (micrometers). The format of some large-sized features in the first exposure pattern 300 does not exceed 100 mm (millimeter). When edge extraction is performed 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.

[0059] In step S130, the maximum principal stress of the microchannel is calculated based on the performance parameters of the printed material. For example, in the traditional printing method, the full-format multi-scale features are usually exposed only once, which may cause the fine line parts of the tiny and closed features to be easily broken. This phenomenon has little to do with the exposure time, light intensity, and interlayer waiting time. The main reason why the fine line parts are easy to break is that the volume shrinks during the curing process of the printing material (such as photosensitive resin), causing the resin in the non-exposed area to form a pressure gradient. When the pressure gradient at the fine line structure position is higher than its fracture threshold, a breakout phenomenon will occur, resulting in defects or molding failure.

[0060] Based on the above factors that may cause the thin line to break easily, this application considers that under the condition of fixed thin line width, it is necessary to determine whether the exposure process parameters will cause the thin line structure to break. Therefore, this application proposes a solid-liquid coupling model based on the finite element method, combined with the solid-liquid boundary movement caused by volume shrinkage during resin curing, to numerically simulate the transient pressure distribution inside the uncured area, calculate the maximum principal stress of the microchannel, and quantitatively evaluate the pressure gradient and fracture risk of the thin line area.

[0061] In some embodiments, calculating the maximum principal stress of the microfluidic channel according to the performance parameters of the printed material includes:

[0062] Step S1301: Calculate the curing volume shrinkage rate of the curing area of ​​the printing material.

[0063] Step S1302: Calculate the transient pressure distribution of the uncured area of ​​the printing material.

[0064] Step S1303: constructing solid-liquid boundary conditions according to the solidification volume shrinkage rate.

[0065] Step S1304: Calculate the pressure gradient according to the transient pressure distribution.

[0066] Step S1305: simulating the stress distribution of the microchannel according to the solid-liquid boundary conditions and the pressure gradient, and calculating the maximum principal stress.

[0067] For example, through the above steps S1301 to S1305, the stress distribution of the microchannel can be simulated and its maximum principal stress can be determined. Subsequently, the fracture risk of the thin line area can be quantitatively evaluated according to the maximum principal stress.

[0068] In some embodiments, for step S1301, calculating the curing volume shrinkage rate of the curing area of ​​the printing material includes: using the following formula (1) to calculate the curing volume shrinkage rate:

[0069] (1)

[0070] in, Indicates the volume shrinkage rate of curing; Indicates the shrinkage volume of the printed material. ; Represents the volume of the initial solidified area of ​​the printed material. Exemplarily, the above step S1301 is equivalent to modeling the solidified area. The solidified area can be regarded as a linear elastic material, and its volume shrinkage during the solidification process may cause transient movement of the solid-liquid boundary, which imposes constraints on the uncured liquid resin, resulting in fluid flow and pressure changes.

[0071] In some embodiments, for step S1302, calculating the transient pressure distribution of the uncured area of ​​the printing material includes:

[0072] Step S1302A: Use the following formulas (2) and (3) to construct the Navier-Stokes equations of the printed material:

[0073] (2)

[0074] (3)

[0075] in, Indicates the density of the printed material; Represents the velocity field of the uncured liquid of the printing material; Indicates time; represents the gradient; represents the transient pressure distribution; Indicates the viscosity of the printing material; Represents the external force field.

[0076] Step S1302B: Solve the Navier-Stokes equations to obtain the transient pressure distribution in the uncured area ;in, Indicates the coordinate position of the uncured area.

[0077] Exemplarily, the above step S1302A 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. The present application can obtain the transient pressure distribution by solving the Navier-Stokes equations.

[0078] In some embodiments, for step S1303, constructing the solid-liquid boundary condition according to the solidification volume shrinkage rate includes: constructing the solid-liquid boundary condition using the following formula (4):

[0079] (4)

[0080] in, represents the solid-liquid boundary condition; Indicates the volume shrinkage rate of curing; Indicates the curing time of the printed material; Represents the normal vector of the solid-liquid boundary. For example, the solid-liquid interface can be used as a moving boundary, and its moving speed is proportional to the solidification volume shrinkage rate.

[0081] In some embodiments, for step S1304, calculating the pressure gradient according to the transient pressure distribution includes: calculating the pressure gradient using the following formula (5):

[0082] (5)

[0083] in, represents the pressure gradient; Indicates the coordinate position of the uncured area; represents the transient pressure distribution; , Indicates the spatial direction. For example, the transient pressure distribution of the fluid It can be obtained by solving the formula (2) mentioned above.

[0084] In some embodiments, for step S1305, simulating the stress distribution of the microchannel according to the solid-liquid boundary condition and the pressure gradient to calculate the maximum principal stress includes: using the following formula (6) to calculate the maximum principal stress:

[0085] (6)

[0086] in, represents the maximum principal stress in the microchannel (i.e., the thin line region); Indicates the initial stress caused by the curing shrinkage of the printed material; represents the pressure gradient; represents the additional stress component caused by the pressure gradient. For example, under the action of solid-liquid coupling, the stress distribution of the thin wire structure may be affected by the pressure gradient, so the maximum principal stress can be calculated using the above formula (6).

[0087] In step S140, in response to the maximum principal stress being less than or equal to a preset threshold, a first exposure process is performed on the printing material using a first exposure pattern to obtain a first printing format of the microfluidic channel device.

[0088] For example, the preset threshold is, for example, the breaking strength of the printing material (such as photosensitive resin). , according to the breaking strength To determine whether the fine wire structure is broken. , then the thin wire structure will not have the risk of breaking; if If the thin line area is found to have a risk of fracture, the exposure strategy can be optimized (such as adjusting the exposure sequence of the partitions or edge extraction) to reduce the pressure gradient in the uncured area, ensure the complete formation of the thin line structure, and improve printing stability and forming accuracy.

[0089] Exemplarily, the threshold determination in the aforementioned step S130 and step S140 is equivalent to a numerical simulation process, and the numerical simulation process is summarized and described here.

[0090] (1) Performance parameters of printing materials (such as photosensitive resin): resin density , Viscosity , elastic modulus E, curing volume shrinkage , Curing time , breaking strength And other parameters.

[0091] (2) Model establishment: Based on the finite element method, a solid-liquid coupling model is constructed, and the initial boundary conditions of the solidified area and the initial boundary conditions of the unsolidified area and the moving boundary conditions are set.

[0092] (3) Transient solution: Solve the Navier-Stokes equations to obtain the transient pressure distribution in the uncured area .

[0093] (4) Pressure gradient calculation: Based on the transient pressure distribution, calculate the pressure gradient inside the unsolidified area .

[0094] (5) Stress distribution analysis: Load pressure gradient and boundary conditions, simulate stress distribution in fine line area, and calculate maximum principal stress .

[0095] (6) Fracture determination: The maximum principal stress Resin breaking strength Compare and determine whether there is a risk of breakage in the thin wire structure.

[0096] Through numerical simulation methods, the present application can accurately evaluate the risk of fine line breakage under exposure process parameters and determine whether given conditions are suitable for the 3D printing process of microfluidic devices.

[0097] In step S150, the first print format is subjected to a second exposure process using a second exposure pattern to obtain a second print format. Exemplarily, the present application uses two exposures, the first exposure is for the internal area, and the second exposure is for the outer contour. Figure 5 This is a schematic diagram of small-size fine-line feature defects produced by the traditional single-exposure process. Figure 6 This is a schematic diagram of a small-size fine line feature produced by the printing method of the present application. Figure 5 and Figure 6 As shown, it can be seen that in the image 600 of the printed format of the present application and the image 500 of the printed format in the traditional way, the fine line features of the present application are clearer and rounder. In practical applications, the format can be divided into multiple independent small areas, and multiple splicing exposure printing is performed. The present application does not limit whether splicing exposure printing is performed.

[0098] The technical solution of the present application can avoid the risk of breakage in the fine line area of ​​the microfluidic device by pre-calculating the maximum principal stress of the microfluidic channel and performing exposure processing only when the maximum principal stress meets the conditions; the present application performs a first edge extraction processing and a second edge extraction processing on the full-format exposure pattern, and divides the printing process into two exposures, the first exposing a large area of ​​the internal area to allow the interior to be pre-cured and shrunk; the second exposing the microfluidic channel with a fine line area allows the fine line structure and the outer contour to be completely and accurately formed.

[0099] The present application can ensure that small-sized fine-line features are not broken while forming large-scale features of the full-format microfluidic device, and will not produce seam defects caused by splicing and dark area exposure, which can improve the printing precision and production efficiency of the microfluidic device. The present application can be used to improve the projection molding precision of full-format multi-scale microfluidic feature surfaces in sub-pixel micro-scanning 3D printing.

[0100] The present application also includes a printing system for a microfluidic device, comprising a memory and a processor, wherein the memory is used to store instructions executable by the processor; and the processor is used to execute the instructions to implement the printing method for the microfluidic device described above.

[0101] Figure 7 is a system block diagram of a printing system for a microfluidic device according to an embodiment of the present application. Figure 7As shown, 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 can realize data communication between the components of the printing system 700 of the microfluidic device. The processor 702 can make judgments and issue prompts. In some embodiments, the processor 702 can be composed of one or more processors. The communication port 705 can realize data communication between the printing system 700 of the microfluidic device and the outside. In some embodiments, the printing system 700 of the microfluidic device can send and receive information and data from the network through the communication port 705. The printing system 700 of the microfluidic device may also include different forms 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, which can store various data files used for computer processing and / or communication, and possible program instructions executed by the processor 702. The processor executes these instructions to implement the main part of the method. The result processed by the processor is transmitted to the user device through the communication port and displayed on the user interface.

[0102] The above-mentioned printing method for the microfluidic device can be implemented as a computer program, stored in the hard disk 706, and loaded into the processor 702 for execution to implement the printing method for the microfluidic device of the present application.

[0103] The present application also includes a computer-readable medium storing a computer program code, which, when executed by a processor, implements the above-mentioned printing method for the microfluidic device.

[0104] When the printing method of the microfluidic device is implemented as a computer program, it can also be stored in a computer-readable storage medium as a product. For example, a computer-readable storage medium may include, but is not limited to, a magnetic storage device (e.g., a hard disk, a floppy disk, a magnetic strip), an optical disk (e.g., a compact disk (CD), a digital versatile disk (DVD)), a smart card, and a flash memory device (e.g., an electrically erasable programmable read-only memory (EPROM), a card, a stick, a key drive). In addition, 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" may include, but is not limited to, wireless channels and various other media (and / or storage media) that can store, contain and / or carry code and / or instructions and / or data.

[0105] It should be understood that the embodiments described above are only 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 in 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 a combination thereof.

[0106] Some aspects of the present application may be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software may be referred to as "data blocks", "modules", "engines", "units", "components" or "systems". 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. In addition, various aspects of the present application may be represented as computer products located in one or more computer-readable media, which include computer-readable program codes. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, tapes ...), optical disks (e.g., compact disks CDs, digital versatile disks DVDs ...), smart cards, and flash memory devices (e.g., cards, sticks, key drives ...).

[0107] A computer-readable medium may include a propagated data signal containing computer program code, such as in baseband or as part of a carrier wave. The propagated signal may have a variety of manifestations, including electromagnetic, optical, etc., or a suitable combination. A computer-readable medium may be any computer-readable medium other than a computer-readable storage medium, which may be connected to an instruction execution system, device or apparatus to communicate, propagate or transmit a program for use. The program code on the computer-readable medium may be propagated via any suitable medium, including radio, cable, fiber optic cable, radio frequency signal, or similar medium, or any combination of the above mediums.

[0108] The basic concepts have been described above. Obviously, for those skilled in the art, the above application disclosure is only an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0109] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0110] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used for the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate 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 can be changed according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the method of general digit retention. Although the numerical domains and parameters used to confirm the breadth of the range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

Claims

1. A printing method for a microfluidic device, characterized in that: include: 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 a microchannel; Calculating the maximum principal stress of the microfluidic channel according to the performance parameters of the printed material; In response 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 format of the microfluidic channel device; performing a second exposure process on the first printing format using the second exposure pattern to obtain a second printing format; Wherein, calculating the maximum principal stress of the microfluidic channel according to the performance parameters of the printed material includes: Calculating a curing volume shrinkage rate of a curing area of ​​the printing material; Constructing a solid-liquid boundary condition according to the solidification volume shrinkage rate; comprising: constructing the solid-liquid boundary condition using the following formula: in, represents the solid-liquid boundary condition; represents the curing volume shrinkage; Indicates the curing time of the printing material; represents the normal vector of the solid-liquid boundary; calculating a transient pressure distribution of an uncured area of ​​the printed material; Calculating the pressure gradient according to the transient pressure distribution; comprising: calculating the pressure gradient using the following formula: in, represents the pressure gradient; Indicates the coordinate position of the uncured area; represents the transient pressure distribution; , Indicates spatial direction; Simulating the stress distribution of the microchannel according to the solid-liquid boundary condition and the pressure gradient to calculate the maximum principal stress; including: calculating the maximum principal stress using the following formula: in, represents the maximum principal stress; Indicates the initial stress generated by the curing and shrinkage of the printed material; represents the pressure gradient; Represents the additional stress component caused by the pressure gradient.

2. The printing method according to claim 1, characterized in that: Calculating the curing volume shrinkage rate of the curing area of ​​the printing material includes: calculating the curing volume shrinkage rate using the following formula: in, represents the curing volume shrinkage; represents the shrinkage volume of the printed material, ; Represents the initial solidification area volume of the printing material.

3. The printing method according to claim 1, characterized in that: Calculating the transient pressure distribution of the uncured area of ​​the printing material, comprising: The Navier Stokes equation for the printed material is constructed using the following formula: in, Indicates the density of the printing material; A velocity field representing an uncured liquid of the printing material; Indicates time; represents the gradient; represents the transient pressure distribution; Indicates the viscosity of the printing material; represents the external force field; Solve the Navier-Stokes equations to obtain the transient pressure distribution in the uncured area ;in, Indicates the coordinate position of the uncured area.

4. The printing method according to claim 1, characterized in that: The first edge extraction process and / or the second edge extraction process adopts a breadth-first search algorithm; Performing a first edge extraction process on a preset exposure pattern to obtain a first exposure pattern includes: Converting the preset exposure pattern into a binary image; traversing pixels in the binary image using a breadth-first search function; In response to the current pixel being an edge pixel, marking the current pixel as an edge, and continuing to traverse 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.

5. A printing system for a microfluidic device, characterized in that: include: a memory for storing instructions to be executed by the processor; A processor, configured to execute the instructions to implement the printing method of the microfluidic device according to any one of claims 1 to 4.

6. A computer readable medium storing computer program code, characterized in that: When the computer program code is executed by a processor, the computer program code implements the printing method for the microfluidic device according to any one of claims 1 to 4.

Images