Polymer microfluidic chip bonding method and device based on resistance heating welding

Abstract

The present application relates to a polymer microfluidic chip bonding method and device based on resistance heating welding, wherein the microfluidic chip is composed of an upper cover plate and a lower base plate, the lower base plate having a microchannel, and the device includes: an operating platform, a numerical control system, a motion platform, a print head, a powder supply system, a pneumatic pressure head, an air pressure device, a resistance detection device, and a power supply. The bonding method includes: using a polymer microfluidic chip bonding device to print a heating resistor element that matches the shape of the microchannel on the lower base plate, then passing a constant current through the heating resistor element to melt the welding area between the upper and lower covers of the microfluidic chip, and using a preset pneumatic pressure head to pressurize and weld the upper and lower covers of the microfluidic chip together to form a complete microfluidic chip. Thus, the problems of low bonding accuracy, poor chemical compatibility, and poor biological adaptability in the interstitial bonding process of microfluidic chips are solved, the process flow of polymer chip bonding is simplified, processing efficiency is improved, and mass production is realized.

Description

Technical Field

[0001] The present application relates to the field of chip technology, and in particular to a polymer microfluidic chip bonding method and device based on resistance heating welding. Background Art

[0002] Microfluidic chips, also known as chip laboratories, integrate basic operating units such as sample preparation, reaction, separation, and detection in biological, chemical, and medical analysis processes onto a micro-nanoscale chip, thereby realizing the miniaturization, portability, and multifunctionality of medical analysis equipment.

[0003] Polymer microfluidic chips have garnered extensive attention and research due to their advantages, such as ease of molding and good biocompatibility. They typically consist of a lower base and an upper cover. During the fabrication of microfluidic chips, bonding the lower base and upper cover to form a closed microcavity structure is a crucial step in chip manufacturing. This closed cavity, comprising microchannels and microfluidic chambers, enables physical and chemical analysis functions such as sampling, flow, and separation. During this bonding process, it is crucial that the microstructures on the chip's lower base and upper cover remain free of contamination, deformation, or clogging, to avoid impacting their analytical capabilities.

[0004] In related technologies, microfluidic chip bonding methods can be divided into interstitial bonding and non-interstitial bonding. Interstitial bonding includes solvent bonding and adhesive bonding; non-interstitial bonding includes hot pressing bonding, surface modification thermal bonding, ultrasonic bonding and other methods.

[0005] However, the disadvantage of interstitial bonding methods is that the introduction of foreign substances may affect the chemical compatibility and bioadaptability of the chip, and the bonding accuracy is low and the uniformity is poor. Non-interstitial bonding methods, such as hot pressing bonding, will not cause contamination to the chip, but cannot simultaneously take into account both bonding strength and structural deformation. Surface modification hot bonding can reduce the deformation of the microstructure, but its processing efficiency is low. Ultrasonic bonding has a short bonding time and high efficiency, and most processes require the introduction of energy-conducting ribs, which increases the complexity of chip mold production. Therefore, the methods in the related art are difficult to take into account the bonding strength, manufacturing accuracy, sealing degree, and processing efficiency of plastic microfluidic chips, or may cause contamination of the microchannel, which urgently needs to be solved. Summary of the Invention

[0006] The present application provides a polymer microfluidic chip bonding method and apparatus based on resistance heating welding to address issues such as low bonding precision, poor chemical compatibility, and poor biocompatibility during interstitial bonding of microfluidic chips. This method is applicable to the bonding and sealing between the upper cover and lower base of microfluidic chips based on polymer matrices such as polystyrene and PMMA (polymethyl methacrylate). This method simplifies the existing polymer chip bonding process, improves processing efficiency, and enables mass production.

[0007] In a first aspect, an embodiment of the present application provides a method for bonding a polymer microfluidic chip based on resistance heating welding, wherein the microfluidic chip is composed of an upper cover plate and a lower base plate, and the lower base plate has a microchannel, wherein the method comprises the following steps:

[0008] The polymer microfluidic chip bonding device operating platform is used as a positioning surface, the lower base plate is adsorbed on the positioning surface by at least one vacuum suction cup, and a heating resistor element matching the shape of the microchannel is printed on the lower base plate by a print head of the polymer microfluidic chip bonding device;

[0009] Measuring the resistance value of the heating resistor element and installing the upper cover plate on the lower base plate based on a preset installation strategy; and

[0010] The current value to be applied to the heating resistor element is determined according to the resistance value, and the current value to be applied is applied to the heating resistor element. A bonding pressure is applied to the upper cover plate using a preset pneumatic pressure head, so that the welding area between the upper cover plate and the lower base plate is pressurized and welded together after the heating resistor element reaches a preset temperature, and the microfluidic chip is obtained after the welding area is cooled, wherein the current value to be applied is a constant current value.

[0011] Optionally, in some embodiments, the step of using the polymer microfluidic chip bonding device to print a heating resistor element matching the shape of the microchannel on the lower base plate includes:

[0012] generating a heating resistor element graphic file according to the micro-channel shape;

[0013] The heating resistor element graphic file is imported into the polymer microfluidic chip bonding device to plan the movement path of the printing nozzle through the polymer microfluidic chip bonding device, and after the movement path planning is completed, the heating resistor element matching the shape of the microchannel is printed out along the movement path by the printing nozzle.

[0014] Optionally, in some embodiments, measuring the resistance value of the heating resistor element includes:

[0015] determining at least one resistance value measurement position of the heating resistor element;

[0016] The resistance value of the at least one resistance value measurement position is measured, and the resistance value of the heating resistor element is obtained according to the resistance value of the at least one resistance value measurement position.

[0017] A second embodiment of the present application provides a polymer microfluidic chip bonding device based on resistance heating welding, comprising:

[0018] Operating platform, CNC system, motion platform, printing nozzle, powder supply system, pneumatic pressure head, air pressure device, resistance detection device and power supply; Among them,

[0019] The motion platform is located at the bottom of the microfluidic chip bonding device and is used to achieve movement in a preset direction;

[0020] The resistance detection device is arranged above the motion platform and is used to detect the resistance value of the heating resistor element;

[0021] The operating platform is arranged above the resistance detection device and is used to install and position the lower base plate of the microfluidic chip;

[0022] The printing nozzle is located above the motion platform and the operating platform, and is used for printing the heating resistor element;

[0023] The powder supply system is arranged above the print head, and after receiving the printing instruction from the numerical control system, the powder supply system combines with the print head to print the heating resistor element;

[0024] The pneumatic pressure head is arranged above the operating platform and on the left side of the print head. When in use, the pneumatic pressure head is driven by the air pressure device to apply pressure to the upper cover plate of the microfluidic chip, so that the upper cover plate is tightly combined with the heating resistor element and the lower base plate of the microfluidic chip;

[0025] The motion platform, the printing nozzle, the powder supply system and the air pressure device all perform corresponding actions according to the control instructions of the numerical control system;

[0026] The power supply is used to provide a constant current to the heating resistor element.

[0027] Therefore, the present application utilizes the printing nozzle of the polymer microfluidic chip bonding device to print a heating resistor element that matches the shape of the microchannel on the lower base plate, then passes a constant current through the heating resistor element to melt the fusion zone between the upper and lower covers of the microfluidic chip, and uses a preset pneumatic pressure head to pressurize and fuse the upper and lower covers of the microfluidic chip together to form a complete microfluidic chip. This solves the problems of low bonding accuracy, poor chemical compatibility, and poor biocompatibility during the interstitial bonding process of microfluidic chips. This method is suitable for bonding and sealing between the upper cover plate and the lower base plate of microfluidic chips with high molecular polymer matrices such as polystyrene and PMMA, simplifying the existing process flow of polymer chip bonding, improving processing efficiency, and realizing mass production.

[0028] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0030] Figure 1 A schematic structural diagram of a polymer microfluidic chip bonding device according to a specific embodiment of the present application, including a front view and a side view;

[0031] Figure 2 Flowchart of a polymer microfluidic chip bonding method based on resistance heating welding according to an embodiment of the present application;

[0032] Figure 3 A schematic diagram of the steps of a polymer microfluidic chip bonding method based on resistance heating welding according to a specific embodiment of the present application;

[0033] Figure 4 A schematic diagram of the positional relationship between a microfluidic channel and a heating resistor element according to a specific embodiment of the present application;

[0034] Figure 5 The figure is a flow chart of a polymer microfluidic chip bonding method based on resistance heating welding according to a specific embodiment of the present application. DETAILED DESCRIPTION

[0035] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0036] The following describes the polymer microfluidic chip bonding method based on resistance heating welding of the embodiment of the present application with reference to the accompanying drawings. In view of the problems of low bonding precision, chemical compatibility and poor biocompatibility in the interstitial bonding process of the microfluidic chip mentioned in the above background technology, the present application provides a polymer microfluidic chip bonding method based on resistance heating welding, in which a heating resistor element that matches the shape of the microchannel is printed on the lower base plate by a print nozzle of a polymer microfluidic chip bonding device, and then a constant current is passed through the heating resistor element to melt the fusion zone between the upper and lower cover plates of the microfluidic chip, and a preset pneumatic pressure head is used to pressurize and weld the upper and lower cover plates of the microfluidic chip together to form a complete microfluidic chip. Thus, the problems of low bonding precision, chemical compatibility and poor biocompatibility in the interstitial bonding process of the microfluidic chip are solved. The method is applicable to the bonding and sealing between the upper cover plate and the lower base plate of a microfluidic chip with a high molecular polymer matrix such as polystyrene and PMMA, simplifies the existing process flow of polymer chip bonding, improves processing efficiency and realizes batch production.

[0037] Before introducing the steps of the polymer microfluidic chip bonding method based on resistance heating welding of the present application, the polymer microfluidic chip bonding device based on resistance heating welding proposed in the embodiment of the present application is first described with reference to the accompanying drawings.

[0038] like Figure 1 As shown, Figure 1 This is a schematic structural diagram of the polymer microfluidic chip bonding device 10 provided in an embodiment of the present application. Figure 1 (a) is a front view of the polymer microfluidic chip bonding device 10, Figure 1 (b) is a side view of the polymer microfluidic chip bonding device 10.

[0039] like Figure 1 As shown, the polymer microfluidic chip bonding device 10 of the embodiment of the present application includes: an operating platform 1, a numerical control system 2, a motion platform 3, a printing nozzle 4, a powder supply system 5, a pneumatic pressure head 6, an air pressure device 7, a resistance detection device 8 and a power supply 9.

[0040] Among them, the motion platform 3 is located at the bottom of the microfluidic chip bonding device and is used to achieve movement in a preset direction; the resistance detection device 7 is arranged above the motion platform 3 and is used to detect the resistance value of the heating resistor element; the operating platform 1 is arranged above the resistance detection device 8 and is used to install and position the lower base plate of the microfluidic chip; the print head 4 is located above the motion platform 3 and the operating platform 1 and is used to print the heating resistor element; the powder supply system 5 is arranged above the print head 4. After receiving the printing instruction issued by the numerical control system 2, the powder supply system 5 combines with the print head 4 to print the heating resistor element; the pneumatic pressure head 6 is arranged above the operating platform 1 and is arranged on the left side of the print head 4. When in use, the pneumatic pressure head 6 is driven by the air pressure device 7 to apply pressure to the upper cover of the microfluidic chip, so that the upper cover is tightly combined with the heating resistor element and the lower base plate of the microfluidic chip; the motion platform 3, the print head 4, the powder supply system 5 and the air pressure device 7 all perform corresponding actions according to the control instructions of the numerical control system 2; the power supply 9 is used to provide a constant current to the heating resistor element.

[0041] It should be noted that the preset directions in the embodiment of the present application are the X and Y directions, and the motion platform 3 of the polymer microfluidic chip bonding device 10 is used to achieve high-precision motion in the X and Y directions.

[0042] The following combination Figure 2 and Figure 3 The steps of the polymer microfluidic chip bonding method based on resistance heating welding in an embodiment of the present application are specifically introduced.

[0043] Figure 2 This is a flow chart of a polymer microfluidic chip bonding method based on resistance heating welding provided in an embodiment of the present application.

[0044] In this embodiment, Figure 3 As shown, the microfluidic chip of the embodiment of the present application consists of a chip cover E and a chip bottom plate B. Positioning pins A and a chip bottom plate B are placed above the operating platform 1, a vacuum suction cup C is placed below, a heating resistor element D is located on the chip bottom plate B, and F is a welding area.

[0045] Specifically, if Figure 2 As shown, the polymer microfluidic chip bonding method based on resistance heating welding includes the following steps:

[0046] In step S201, the polymer microfluidic chip bonding device operating platform is used as the positioning surface, the lower base plate is adsorbed on the positioning surface by at least one vacuum suction cup, and the polymer microfluidic chip bonding device is used to print a heating resistor element matching the shape of the microchannel on the lower base plate.

[0047] It should be noted that if Figure 3As shown, the bottom plate B of the microfluidic chip of the present embodiment has microchannels, and the material of the microfluidic chip can be selected from polymers such as PMMA and polystyrene. The heating resistor element D of the present embodiment is ejected through the print head 4 of the polymer microfluidic chip bonding device 10.

[0048] Specifically, combined Figures 1 to 3 , the embodiment of the present application requires the operating platform 1 of the polymer microfluidic chip bonding device 10 as the positioning surface, and the chip bottom plate B is adsorbed on the positioning surface by at least one vacuum suction cup C, thereby achieving the function of clamping the microfluidic chip bottom plate B. According to the size and shape of the microchannel, the polymer microfluidic chip bonding device 10 is used to control the print head 4 and the motion platform 3 to print out a continuous heating resistor element D that matches the shape of the microchannel on the microfluidic chip bottom plate B. The motion platform 3 of the embodiment of the present application is located at the bottom of the microfluidic chip bonding device 10, and can achieve high-precision movement in the XY direction. The positional relationship between the microchannel and the heating resistor element D of the chip bottom plate B in the embodiment of the present application is as shown in the figure. Figure 4 As shown, the heating resistor element D is located between the upper cover plate E and the lower base plate B of the microfluidic chip.

[0049] In the actual implementation process, Figure 1 and Figure 3 As shown, the positioning surface is the operating platform 1 of the polymer microfluidic chip bonding device 10, and the vacuum suction cup C is used to adsorb the chip lower base plate B onto the positioning surface, thereby more firmly clamping the chip lower base plate B. The microfluidic chip lower base plate B of the embodiment of the present application is positioned using a "one-side, two-pin" positioning method. The operating platform 1 of the polymer microfluidic chip bonding device 10 serves as the positioning surface and also serves as the reference for positioning the microfluidic chip upper cover plate E and lower base plate B. The microfluidic chip lower base plate B is adsorbed by the vacuum suction cup C.

[0050] Specifically, combined Figure 1 He Ru Figure 3 As shown in (a), the chip bottom plate B to be bonded is placed horizontally on the operating platform 1 of the polymer microfluidic chip bonding device 10. The "one-side two-pin" positioning method is used to limit the six degrees of freedom of the chip bottom plate B. The operating platform 1 of the polymer microfluidic chip bonding device 10 is used as the positioning surface. At the same time, positioning pins A are used on both sides of the chip bottom plate B to limit the X and Y directions of freedom to achieve complete positioning. The chip bottom plate B is clamped using a vacuum suction cup C. The required vacuum degree can be calculated using the following formula:

[0051] P=M*μ / S

[0052] Where, M is gravity (N), S is the actual adsorption area (cm 2 ), P is the vacuum degree (mbar), μ is the safety factor, and μ ≥ 2.5.

[0053] The vacuum chuck C clamps the chip bottom plate B on the bonding device operating platform 1 to prevent the chip bottom plate B from shifting during the subsequent bonding process.

[0054] For example, combining Figure 1 and Figure 3 , the chip bottom plate B (PMMA material, chip specifications are 45mm*37mm*1.5mm) with microfluidic channels is installed on the operating platform 1 of the polymer microfluidic chip bonding device 10 through the mutual cooperation of the positioning holes and the positioning pins A, and the chip bottom plate B is adsorbed using a vacuum suction cup C, and the vacuum degree of the suction cup is set to 0.22mbar, thereby clamping the chip bottom plate B to prevent the chip bottom plate B from shifting.

[0055] Optionally, in some embodiments, a polymer microfluidic chip bonding device is used to print a heating resistor element that matches the shape of the microchannel on the lower base plate, including: generating a heating resistor element graphic file according to the shape of the microchannel; importing the heating resistor element graphic file into the polymer microfluidic chip bonding device to plan the movement path of the printing nozzle through the polymer microfluidic chip bonding device, and after the movement path planning is completed, printing the heating resistor element that matches the shape of the microchannel along the movement path through the printing nozzle.

[0056] Among them, combined Figures 1 to 3 After the graphic file design of the heating resistor element D in the embodiment of the present application is completed, it needs to be imported into the CNC system 2, and the movement path of the print head 4 is planned in the system. The conductive paste powder required by the print head 4 is provided by the powder supply system 5.

[0057] In the actual implementation process, Figure 1 and Figure 3 As shown in (b), a corresponding heating resistor element D graphic file is designed according to the shape and size of the microchannel of the chip bottom plate B, that is, the shape of the heating resistor element D graphic is consistent with the microchannel; then the graphic file is imported into the numerical control system 2 of the microfluidic chip bonding device 10; according to the graphic file imported into the numerical control system 2, the movement path of the print nozzle 4 is planned in the system, and at the same time, the powder supply system 5 starts to work and provides conductive paste powder to the print nozzle 4. After the movement path planning is completed, the print nozzle 4 starts to move on the upper surface of the microfluidic chip bottom plate B, forming a continuous heating resistor element D that matches the shape and size of the microchannel, and at the same time prints out a wire connected to the power supply, extending to the edge of the microfluidic chip bottom plate B. The print nozzle 4 is based on the piezoelectric ceramic inkjet principle, and the printing process parameters, rate and thickness are controlled by the numerical control system 2.

[0058] It should be noted that the resistivity of the conductive paste powder material is 1.0*10 -7~1.0*10 -5 The present application does not impose any specific restrictions on the selection of conductive paste powder materials, and those skilled in the art can make their own choices based on actual needs. The resistance value of the heating resistor element D is within the range of 0.5Ω to 30Ω, and carbon powder, graphite, and other materials can be selected, without specific restrictions here.

[0059] For example, combining Figure 1 and Figure 3 The microchannel shape of the bottom plate B of the microfluidic chip to be bonded is a straight channel, and the specifications of the groove are 25mm*150μm*150μm. The microfluidic chip bonding device 10 is designed with a corresponding heating resistor element D graphic file. The shape of the heating resistor element D is consistent with the shape of the microchannel, but there is a certain distance between it and the microchannel to prevent the molten material generated during the subsequent heating and welding process from contaminating the microchannel. Based on this, the specifications of the heating resistor element are designed to be 30mm*0.1mm*0.2mm. The graphic file of the heating resistor element D is imported into the CNC system 2. After the printing path is planned in the system, the print head 4 and the powder supply system 5 perform the corresponding movement, spraying the nickel-chromium alloy conductive paste powder on the bottom plate B of the chip with the microchannel structure, forming the heating resistor element D. At the same time, wires for connecting to the power supply are printed at both ends of the heating resistor element D to facilitate subsequent power heating.

[0060] In step S202 , the resistance value of the heating resistor element is measured, and based on a preset installation strategy, the upper cover plate is installed on the lower base plate.

[0061] Optionally, in some embodiments, measuring the resistance value of the heating resistor element includes: determining at least one resistance value measurement position of the heating resistor element; measuring the resistance value of at least one resistance value measurement position, and obtaining the resistance value of the heating resistor element based on the resistance value of at least one resistance value measurement position.

[0062] It should be noted that if Figure 3 As shown, the embodiment of the present application uses a resistance detection device 8 to select different points to measure the resistance value of the heating resistor element D multiple times. Then, it is necessary to process the multiple measured resistance values. Specifically, the average of the multiple resistance values ​​is calculated as the actual resistance value. The embodiment of the present application needs to calculate the theoretical resistance value according to a set calculation formula, and compare the actual resistance value with the theoretical resistance value. If the comparison result is within the normal range, the heating resistor element D is determined to be normal. Otherwise, it is necessary to continue to detect breakpoints and points with excessively high local resistance, and to supplement materials or reprint to bring the resistance value of the heating resistor element D back into the normal range.

[0063] Specifically, if Figure 3As shown in (c), the embodiment of the present application uses the dual probes of the resistance detection device 8 to measure the resistance value of the heating resistor element D multiple times at different points, observes the readings of the resistance detection device 8, takes the average value as the actual resistance value, and then calculates the theoretical resistance value according to the resistance calculation formula R = ρ * L / S. If the measured actual resistance value is within the range of 0.5 to 1.5 times the theoretical resistance value, the heating resistor element D can be used normally. If it exceeds this range, it needs to be reprocessed to prevent breakage of the heating resistor element D from affecting the bonding effect.

[0064] For example, the resistance values ​​of different points of the heating resistor element D are measured using the dual probes on both sides of the resistance detection device 8, and the average value is calculated as the actual resistance value. The measurement result is 0.69Ω. The resistivity of nickel-chromium alloy is ρ = 1.0*106Ω·m, and the cross-sectional area of ​​the heating resistor element D is S = 2*10 -8 m 2 , length L = 0.03m. According to theoretical calculation, its theoretical resistance value should be 0.75Ω. The actual resistance value of 0.69Ω is within the range of 0.38Ω to 1.2Ω. Therefore, this resistor can be used as a heating resistor element in the welding area between the upper cover plate and the lower base plate of the welding chip.

[0065] Furthermore, the preset installation strategy of the embodiment of the present application is to align the upper cover plate E of the microfluidic chip and install it on the lower base plate B with the heating resistor element D, and apply a certain pre-pressure to the upper cover plate E. The preset pressure of the embodiment of the present application can be 30N.

[0066] In the actual implementation process, Figure 3 As shown in (d), the chip cover E is positioned and installed, and the positioning holes and positioning pins A of the chip cover E are used for positioning. The chip cover E is aligned and installed above the chip bottom plate B with the heating resistor element D. The motion platform 3 is controlled to drive the microfluidic chip with the complete structure to move directly below the pneumatic pressure head 6. The pneumatic pressure head 6 moves downward to apply pre-pressure to the chip cover E to prevent the chip cover E from shifting during the subsequent heating process. When applying pressure, symmetrical point pressure is used to ensure that the cover E is evenly stressed.

[0067] In step S203, the current value to be applied to the heating resistor element is determined according to the resistance value, and the current value to be applied is applied to the heating resistor element, and a bonding pressure is applied to the upper cover plate using a preset pneumatic pressure head to pressurize and fuse the welding area between the upper cover plate and the lower base plate together after the heating resistor element reaches a preset temperature, and the microfluidic chip is obtained after the welding area is cooled, wherein the current value to be applied is a constant current value.

[0068] In the actual implementation process, combined with Figure 1 and Figure 3In the embodiment of the present application, the heating resistor element D is connected to the power supply 9 and a constant current is passed through it to generate heat and partially melt the welding area F. Then, a pneumatic pressure head 6 is used to apply bonding pressure to the upper cover plate E, and the upper cover plate E and the lower base plate B are pressurized and welded together to form a complete microfluidic chip. Finally, the power supply 9 is turned off, the pressure is maintained, and the welding area F is cooled to obtain the final microfluidic chip.

[0069] Specifically, if Figure 3 As shown in (e), turn on the power supply 9, connect the positive and negative probes to the pre-buried wires of the heating resistor element D, and pass a constant current through the heating resistor element D. The current can be calculated according to the following formula:

[0070]

[0071] Where I is the constant current, M is the mass of the weld zone, T1 is the melting point of the material, T0 is the initial temperature, C is the specific heat capacity of the chip cover E and chip base B materials, R is the resistance of the resistor element, and t is the power-on time.

[0072] It can be understood that the current value to be applied and the power-on time in the embodiment of the present application can be calculated by a specific formula. For example, the current value can be set to 3A and the power-on time can be set to 60s through calculation.

[0073] Furthermore, if Figure 3 As shown in (f), after the heating resistor element D generates enough heat, it partially melts the welding area F between the chip cover E and the chip bottom plate B. Then, the air pressure device 7 pushes the pneumatic pressure head 6 downward to apply a certain bonding pressure to the chip cover E, thereby welding and compacting the chip cover E, the heating resistor element D and the chip bottom plate B, so that the three are tightly combined to form a complete microfluidic chip and improve the sealing of the microfluidic chip.

[0074] It should be noted that the present application does not specifically limit the magnitude of the bonding pressure applied by the pneumatic pressure head 6 to the upper cover plate E. Those skilled in the art can set it according to actual needs. For example, the bonding pressure can be 300N.

[0075] Finally, if Figure 3 As shown in (g), the power supply 9 is turned off, the bonding pressure is continued to be applied, and the chip is cooled at room temperature to finally obtain a complete microfluidic chip. In addition, this application does not specifically limit the cooling time, and those skilled in the art can set the cooling time according to factors affecting the temperature.

[0076] Furthermore, in order to facilitate those skilled in the art to further understand the polymer microfluidic chip bonding method based on resistance heating welding in the embodiment of the present application, it is described in detail below with reference to the specific embodiments of the drawings.

[0077] Specifically, if Figure 5 As shown, the polymer microfluidic chip bonding method based on resistance heating welding includes the following steps:

[0078] Step S501, positioning the lower base plate of the microfluidic chip and clamping it on the operating platform;

[0079] Step S502: importing the designed heating resistor element pattern into the CNC system according to the size and shape of the microchannel;

[0080] Step S503, using a print head to print a heating resistor element;

[0081] Step S504, measuring the resistance value of the resistor element to detect whether the resistance value is within a normal range. If the detected resistance value is within the range, executing step S506, otherwise executing step S505;

[0082] Step S505 , detecting breakpoints or points where the local resistance value is too large, replenishing materials or re-printing to make the resistance value of the resistor element within the normal range, and executing step S506 ;

[0083] Step S506: Position and install the upper cover plate above the lower base plate, and apply pre-pressure using a pneumatic pressure head;

[0084] Step S507: heating the welding area with a constant current and applying bonding pressure to weld the upper and lower cover plates together;

[0085] Step S508 , maintaining the bonding pressure, cutting off the power supply, and cooling at room temperature for 120 seconds, and the chip bonding is completed.

[0086] Thus, the polymer microfluidic chip bonding method and apparatus based on resistance heating welding provided in the embodiments of this application improve the sealing performance of the microfluidic chip by first heating and welding, and then pressurizing and tightening. This improves both manufacturing precision and bonding strength, ensuring the reliable functioning of the polymer microfluidic chip. Furthermore, the bonding method and apparatus of this application can also improve production efficiency and achieve automated and mass production.

[0087] According to the polymer microfluidic chip bonding method based on resistance heating welding proposed in the embodiment of the present application, a heating resistor element that matches the shape of the microchannel is printed on the lower base plate using the printing nozzle of the polymer microfluidic chip bonding device. A constant current is then passed through the heating resistor element to melt the fusion zone between the upper and lower covers of the microfluidic chip. A preset pneumatic pressure head is used to pressurize and fuse the upper and lower covers of the microfluidic chip together to form a complete microfluidic chip. This solves the problems of low bonding accuracy, poor chemical compatibility, and poor biocompatibility during the interstitial bonding process of microfluidic chips. This method is suitable for bonding and sealing between the upper cover plate and the lower base plate of microfluidic chips with high molecular weight polymer matrices such as polystyrene and PMMA, simplifying the existing process flow of polymer chip bonding, improving processing efficiency, and realizing mass production.

[0088] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0089] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0090] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing a custom logical function or process step, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed in a different order than shown or discussed, including performing functions in a substantially simultaneous manner or in a reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0091] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array, a field programmable gate array, etc.

[0092] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0093] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A polymer microfluidic chip bonding method based on resistance heating welding, characterized in that: The microfluidic chip is composed of an upper cover plate and a lower base plate, wherein the lower base plate has a microfluidic channel, wherein the method comprises the following steps: Using the operating platform of the polymer microfluidic chip bonding device as a positioning surface, the lower base plate is adsorbed on the positioning surface by at least one vacuum suction cup, and the polymer microfluidic chip bonding device is used to print a heating resistor element matching the shape of the microchannel on the lower base plate; Measuring the resistance value of the heating resistor element and installing the upper cover plate on the lower base plate based on a preset installation strategy; and The current value to be applied to the heating resistor element is determined according to the resistance value, and the current value to be applied is applied to the heating resistor element. A bonding pressure is applied to the upper cover plate using a preset pneumatic pressure head, so that the welding area between the upper cover plate and the lower base plate is pressurized and welded together after the heating resistor element reaches a preset temperature, and the microfluidic chip is obtained after the welding area is cooled, wherein the current value to be applied is a constant current value.

2. The method according to claim 1, characterized in that The method of using the polymer microfluidic chip bonding device to print a heating resistor element matching the shape of the microchannel on the lower base plate includes: generating a heating resistor element graphic file according to the micro-channel shape; The heating resistor element graphic file is imported into the polymer microfluidic chip bonding device to plan the movement path of the printing nozzle through the polymer microfluidic chip bonding device, and after the movement path planning is completed, the heating resistor element matching the shape of the microchannel is printed out along the movement path by the printing nozzle.

3. The method according to claim 1, characterized in that Measuring the resistance value of the heating resistor element includes: determining at least one resistance value measurement position of the heating resistor element; The resistance value of the at least one resistance value measurement position is measured, and the resistance value of the heating resistor element is obtained according to the resistance value of the at least one resistance value measurement position.

4. A polymer microfluidic chip bonding device based on resistance heating welding, characterized in that: include: Operating platform, CNC system, motion platform, printing nozzle, powder supply system, pneumatic pressure head, air pressure device, resistance detection device and power supply; Among them, The motion platform is located at the bottom of the microfluidic chip bonding device and is used to achieve movement in a preset direction; The resistance detection device is arranged above the motion platform and is used to detect the resistance value of the heating resistor element; The operating platform is arranged above the resistance detection device and is used to install and position the lower base plate of the microfluidic chip; The printing nozzle is located above the motion platform and the operating platform, and is used for printing the heating resistor element; The powder supply system is arranged above the print head, and after receiving the printing instruction from the numerical control system, the powder supply system combines with the print head to print the heating resistor element; The pneumatic pressure head is arranged above the operating platform and on the left side of the print head. When in use, the pneumatic pressure head is driven by the air pressure device to apply pressure to the upper cover plate of the microfluidic chip, so that the upper cover plate is tightly combined with the heating resistor element and the lower base plate of the microfluidic chip; The motion platform, the printing nozzle, the powder supply system and the air pressure device all perform corresponding actions according to the control instructions of the numerical control system; The power supply is used to provide a constant current to the heating resistor element.

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