3D printing microfluidic chip microfluidic channel polishing device, polishing method and application thereof

Abstract

The application discloses a 3D printing microfluidic chip microfluid channel polishing device, a polishing method and application thereof, wherein the 3D printing microfluidic chip microfluid channel polishing device comprises a motion control assembly, a vibrating platform, a connecting piece and a polishing head, a clamp for placing a chip is arranged on the motion control assembly; the vibrating platform is located below the motion control assembly; the connecting piece is fixedly arranged on the vibrating platform; the polishing head is installed on the connecting piece, the polishing head corresponds to the clamp, the polishing head comprises an excitation module and a magnetic pole module, and the polishing head is arranged in a stable magnetic field. The application combines the advantages of 3D printing and magnetic field auxiliary polishing technology, performs fine microscopic cutting and polishing on the chip, effectively removes the surface defects of the microfluid channel, can significantly improve the surface quality of the microfluidic chip, and provides a possibility for large-scale and standardized preparation of high-performance 3D printing microfluidic chips.

Description

Technical Field

[0001] This invention belongs to the field of chip processing technology, specifically relating to a microchannel polishing device, polishing method and application of 3D printed microfluidic chips. Background Technology

[0002] Microfluidics technology enables precise fluid manipulation and analysis at the microscale, offering advantages such as high separation and detection accuracy and low cost, and has been widely applied in fields such as chemistry, biology, medicine, and environmental science. Polydimethylsiloxane (PDMS) is the most widely used microfluidic chip material, possessing good flexibility, high transparency, excellent biocompatibility, and ease of fabrication. However, its high manufacturing cost and complex processes cannot meet the growing application demands. Therefore, it is necessary to find a convenient, rapid, and low-cost method for fabricating microfluidic chips.

[0003] Compared to traditional photolithography and soft photolithography, 3D printing technology reduces cumbersome process steps and can accurately construct multi-layered, complex geometries in a single manufacturing process. However, 3D printing often has certain limitations in actual manufacturing, such as stacking marks between printed layers leading to step patterns, relatively large surface roughness of microchannels, and even tiny defects in some fine structures. Therefore, effectively reducing the surface roughness of microchannels in 3D-printed microfluidic chips and improving the quality of surface microstructures is crucial for enhancing the performance of 3D-printed microfluidic chips.

[0004] Traditional 3D printed chip polishing methods include mechanical polishing, chemical polishing, and thermal polishing, but all have some core drawbacks. Currently, the more mature 3D printed microfluidic chips are all based on resin materials. The inherent properties of resin materials make it difficult to precisely control their properties using chemical and thermal polishing methods, and these methods may introduce secondary contamination or damage. Furthermore, microfluidic chips are small in size, and their microchannels are closed structures, making them difficult to polish using traditional mechanical polishing equipment, which cannot effectively handle their complex internal structures.

[0005] Therefore, a microchannel polishing device is needed that can polish the fine, closed internal microchannels of 3D printed chips without any blind spots. Summary of the Invention

[0006] To address the aforementioned issues, embodiments of the present invention propose a microchannel polishing device, polishing method, and application for 3D printed microfluidic chips.

[0007] The microchannel polishing device for 3D printed microfluidic chips of the present invention includes: a motion control component, on which a fixture for placing the chip is disposed; a vibration platform located below the motion control component; a connector fixedly disposed on the vibration platform; and a polishing head mounted on the connector, the polishing head corresponding to the fixture, the polishing head including an excitation module and a magnetic pole module, and the polishing head disposed in a stable magnetic field.

[0008] The motion control component is a three-dimensional motion platform, including an X-axis motion component, a Y-axis motion component and a Z-axis motion component, with the fixture mounted on the Z-axis motion component.

[0009] The vibration platform is horizontally positioned below the motion control component. The connector is a 3D-printed polymer material connector, which is L-shaped. The magnetic pole module and the excitation module are positioned opposite each other on the connector, with the magnetic pole module located above the excitation module. The magnetic pole module and the excitation module correspond to the fixtures on the motion control component.

[0010] The excitation module includes a large permanent magnet fixed on the connector and a small permanent magnet located above the large permanent magnet. Both the small permanent magnet and the large permanent magnet are cylindrical. The magnetic pole module is a pure iron rod, which is installed vertically on the upper part of the connector.

[0011] Both the large and small permanent magnets are neodymium iron boron magnets. The large permanent magnet has a diameter of 30 mm and a height of 30 mm, and is made of N52 material. The small permanent magnet has a diameter of 10 mm and a height of 10 mm, and is also made of N52 material.

[0012] The vibration platform is a rectangular plate with multiple through holes on its surface. It is part of a small precision vibration testing system and is connected to an exciter and a sensor.

[0013] A method for polishing a 3D-printed microfluidic chip using the microchannel polishing apparatus of the present invention includes the following steps:

[0014] S1. Place the 3D printed chip to be polished on the fixture and make precise adjustments using the motion control components to center it in the polishing area;

[0015] S2. Based on the chip's material and surface condition, set appropriate parameters such as magnetic field strength, vibration frequency, and polishing time using the vibration platform's software. When the vibration platform moves, the sensor monitors the motion parameters in real time.

[0016] S3. Before polishing, the polishing slurry is injected into the microchannels of the 3D printed chip to be polished. For 3D printed chips with semi-closed channel structures, the polishing slurry is directly injected into the position to be polished. For closed 3D printed chips, the polishing slurry can be injected into the microchannels of the 3D printed chip through the chip inlet in advance using a syringe.

[0017] S4. Start the excitation module and motion control component. Use the motion control component to control the polishing head so that the polishing fluid performs precision micro-cutting and polishing on the chip surface under the action of the magnetic field.

[0018] S5. After polishing is complete, shut down the system, remove the polished chip, and clean and dry it.

[0019] The polishing fluid in S3 includes a bonding magnetic abrasive polishing fluid and a shear-thickened polishing fluid, wherein the preparation method of the magnetic bonding polishing fluid includes the following steps:

[0020] T1. Take the iron matrix and abrasive grains, mix them thoroughly to obtain a uniform mixed powder;

[0021] T2. During the mixing of the powder, gradually add the adhesive, i.e., 502 glue, to ensure that the mixture bonds evenly;

[0022] T3. Place the mixture in a constant temperature drying oven for curing;

[0023] T4. Remove the cured magnetic abrasive block, perform preliminary crushing, and place it in a cool, dry place to air dry;

[0024] T5. The pulverized abrasive is sieved for particle size separation using a standard sorting sieve;

[0025] T6. The obtained bonding powder is stirred and mixed with the silicone oil-based carrier liquid to finally prepare the magnetic bonding polishing liquid.

[0026] The method for preparing the shear-thickening polishing fluid includes the following steps:

[0027] T1. Dissolve nano-silica particles in anhydrous ethanol medium;

[0028] T2. Place the dispersed solution in a naturally ventilated environment to dry;

[0029] T3. Grind the dried blocky silica into powder;

[0030] T4. Mix powdered nano-silica and organic dispersant PEG-200 at a mass ratio of 1:5 and mechanically stir to fully dissolve them to obtain the base liquid;

[0031] T5. Transfer the prepared base liquid to a vacuum device for vacuum treatment for 1 hour to eliminate air bubbles generated during mechanical stirring and obtain a transparent nano-silica-based shear thickening liquid;

[0032] T6. Silicon carbide abrasive particles and carbonyl iron particles (CIPs) were added sequentially to the nano-silica-based shear thickening liquid, and mechanical stirring and vacuum degassing were repeated to finally prepare a nano-silica-based polishing liquid sample.

[0033] Applications of 3D printed chips prepared using the polishing method of the present invention in biomedicine.

[0034] The beneficial effects of this invention are that it discloses a microchannel polishing device and method for 3D-printed microfluidic chips, which has the advantages of simple steps, low cost, and high degree of automation. This method can ensure efficient and precise polishing of small, curved, or closed microchannel areas while minimizing the impact on the surface quality of other surrounding areas of the channel. It can be applied to the fabrication of microfluidic chips with high surface quality requirements. Optimized magnetic bonding polishing slurry and shear-thickening polishing slurry were developed. A magnetic field-assisted method was used to polish the surface of the 3D-printed chip's microchannels. Through the application of an external magnetic field, magnetic particles and abrasive particles in the polishing slurry form a uniform polishing pad on the chip channel surface, performing fine micro-cutting and polishing of the chip. This effectively removes surface defects in the microchannels and improves the surface flatness of the chip. Combining the advantages of 3D printing and magnetic field-assisted polishing technology not only significantly improves the surface quality of microfluidic chips but also provides the possibility for large-scale, standardized fabrication of high-performance 3D-printed microfluidic chips. The 3D-printed chip based on magnetic field-assisted polishing technology provided by this invention can be applied in biomedical detection, drug screening, chemical synthesis, and other fields, and has broad application prospects. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the microchannel polishing device for the 3D printed microfluidic chip of the present invention.

[0036] Figure 2 This is a top view of the microchannel polishing device for the 3D printed microfluidic chip of the present invention.

[0037] Figure 3 This is a schematic diagram of the motion control component of the present invention.

[0038] Figure 4 This is a schematic diagram of the polishing head of the present invention.

[0039] Figure 5 This is a schematic diagram of the working principle of the magnetic pole module of the present invention.

[0040] Figure 6These are isometric views (top) and cross-sectional views (bottom) of a closed 3D printed chip workpiece polished by the device of the present invention.

[0041] Figure 7 This is a physical image of the magnetic bonding polishing liquid prepared according to the present invention.

[0042] Figure 8 This is a physical image of the shear-thickening polishing fluid prepared according to the present invention.

[0043] Figure 9 The image shows a comparison of the surface morphology of the microchannels of the microfluidic chip prepared according to the present invention before polishing (left image) and after polishing (right image).

[0044] Figure 10 The image shows a comparison of the transparency of the microfluidic chip prepared according to this invention before polishing (left image) and after polishing (right image).

[0045] Figure 11 Comparison of cell staining images under an inverted fluorescence microscope before and after polishing of the microfluidic chip prepared for this invention (left image) and after polishing (right image) when used for cell culture.

[0046] Figure 12 The graph shows the change in surface roughness over time for samples processed by the two polishing slurries prepared in this invention.

[0047] Figure label:

[0048] Motion control component 1; X-axis guide rail 101; Motor 1 102; Roller 1 103; Y-axis guide rail 104; Motor 2 105; Roller 2 106; Motor 3 107; Z-axis sliding plate 108; Slider guide rail 109; Slider 110; Bracket 1 111; Bracket 2 112; Fixture 2; Vibration platform 3; Excitation module 4; Magnetic pole module 5; Connector 6; Chip 7; Microchannel 701; Sensor 8; Polishing fluid 9. Detailed Implementation

[0049] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0050] like Figures 1-12 As shown, the microchannel polishing device for 3D printed microfluidic chips of the present invention includes: a motion control component 1, a vibration platform 3, a connector 6, and a polishing head. The motion control component 1 is provided with a fixture 2 for placing the chip 7. The motion control component 1 is used to adjust the position of the chip 7 on the fixture 2 so that it corresponds to the position of the polishing head, so that the polishing head polishes the microchannel 701 in the chip 7.

[0051] The vibration platform 3 is located below the motion control component 1. The vibration platform 3 in this application is part of the VE series small precision vibration table from Yiheng Company, specifically model VE-5110. The VE series small precision vibration table is equipped with an exciter, which is connected to the vibration platform 3 to achieve reciprocating motion of the vibration platform 3 in the left-right / horizontal directions. The excitation module in the polishing head provides a stable magnetic field for chip polishing.

[0052] The vibration platform 3 is a rectangular plate with multiple through holes on its surface. The vibration platform 3 is also connected to a sensor 8 (the sensor is one of the following: temperature and vibration transmitter, eddy current vibration sensor, integrated eddy current sensor and vibration meter, which can monitor the displacement, frequency and amplitude of the vibration platform in real time). The sensor 8 is set on the outer shell of the VE series small precision vibration table and corresponds to the vibration platform 3.

[0053] The connector 6 is fixed to the vibration platform 3 by bolts, allowing it to reciprocate with the vibration platform 3. The connector 6 is a 3D-printed polymer material connector, and its overall shape is L-shaped.

[0054] The polishing head is mounted on the connector 6 and corresponds to the clamp 2. The polishing head includes an excitation module 4 and a magnetic pole module 5. The magnetic pole module 5 and the excitation module 4 are arranged opposite each other on the connector 6. The magnetic pole module 5 is located above the excitation module 4 and corresponds to the clamp 2 on the motion control assembly 1.

[0055] The excitation module 4 includes a large permanent magnet fixed on the connector 6 and a small permanent magnet located above the large permanent magnet. Both the small permanent magnet and the large permanent magnet are cylindrical and are neodymium iron boron magnets. The large permanent magnet has a diameter of 30mm and a height of 30mm and is made of N52 material. The small permanent magnet has a diameter of 10mm and a height of 10mm and is also made of N52 material.

[0056] The magnetic pole module 5 is a pure iron rod, which is installed vertically on the upper part of the connector 6. The magnetic pole module 5 corresponds to the small permanent magnet below it. After the chip 7 is placed in the fixture 2, it will finally move to be polished between the magnetic pole module 5 and the excitation module 4.

[0057] The motion control component 1 is a three-dimensional motion platform. The vibration platform 3 controls the vibration of the polishing head. The three-dimensional platform controls the polishing head to move along a predetermined route so that all the flow channels inside the chip 7 are processed.

[0058] The motion control component 1 is connected to a G-code program, which controls the motion path and speed of the motion control component 1. The vibration platform's accompanying software is the exciter's built-in control program, used to control vibration parameters. The two are independent but collaborative systems: the G-code controls the chip's movement trajectory within the polishing area, while the vibration software controls the vibration parameters of the polishing head, jointly achieving automated control of the polishing process.

[0059] like Figure 3 As shown, the motion control component 1 includes an X-axis motion component, a Y-axis motion component, and a Z-axis motion component, with a clamp 2 mounted on the Z-axis motion component. The X-axis motion component includes two parallel X-axis guide rails 101, each with four rollers 103. The four rollers 103 are clamped at the upper and lower ends of the X-axis guide rail 101. One roller 103 is connected to the output shaft of a motor 102, which drives the roller 103 to move along the X-axis guide rail 101. The two motors 102 are mounted on two brackets 111, respectively. The two motors 102 are synchronous motors.

[0060] The two X-axis guide rails 101 are connected by a Y-axis guide rail 104. The two ends of the Y-axis guide rail 104 are respectively mounted on two brackets 111. Four rollers 106 are set on the Y-axis guide rail 104. The rollers 106 move along the Y-axis guide rail 104. One of the rollers 106 is connected to the output shaft of the motor 105. The motor 105 is mounted on the bracket 112. The bracket 112 is also equipped with a motor 107. The output shaft of the motor 107 is connected to a ball screw. The ball screw is perpendicular to the Y-axis guide rail 104 and the X-axis guide rail 101. The ball screw is connected to the Z-axis sliding plate 108 through a nut. The Z-axis sliding plate 108 is provided with multiple bolt holes. The slider guide rail 109 is mounted on the Z-axis sliding plate 108 through the bolt holes. Two sliders 110 are arranged at intervals along the Y-axis direction on the slider guide rail 109. The front end of the slider 110 is fixedly equipped with a clamp 2.

[0061] The clamp 2 consists of a U-shaped bracket and a movable plate. The top of the movable plate is connected to a screw via a bearing. The U-shaped bracket is fixedly connected to the slider 110. A threaded through hole is provided at the top of the U-shaped bracket, through which the screw passes, and a circular handle is provided at the end of the screw. By rotating the handle, the screw can drive the movable plate to move up and down inside the U-shaped bracket, thereby clamping the chip 7.

[0062] After the clamp 2 clamps the chip 7, the chip 7 can be moved by controlling motor 102, motor 2105 and motor 3107 until the chip 7 can be placed between the excitation module 4 and the magnetic pole module 5.

[0063] A method for polishing a 3D-printed microfluidic chip using a microchannel polishing apparatus of the present invention includes the following steps:

[0064] S1. Place the 3D printed chip 7 to be polished on the fixture 2, and make precise adjustments through the motion control component 1 to make it located in the center of the polishing area;

[0065] S2. Based on the chip's material and surface condition, appropriate parameters such as magnetic field strength, vibration frequency, and polishing time are set using the vibration platform's accompanying software (the exciter's built-in control program, which allows setting frequency, time, etc.). When the vibration platform moves, the sensor monitors the motion parameters in real time.

[0066] S3. Before polishing, the polishing slurry is injected into the microchannels of the 3D printed chip to be polished. For 3D printed chips with semi-closed channel structures, the polishing slurry is directly injected into the position to be polished. For closed 3D printed chips, the polishing slurry can be injected into the microchannels of the 3D printed chip through the chip inlet in advance using a syringe.

[0067] S4. Start the excitation module and motion control component 1, and use the motion control component 1 to control the polishing head so that the polishing liquid performs precision micro-cutting and polishing on the surface of chip 7 under the action of a magnetic field;

[0068] S5. After polishing is complete, shut down the system, remove the polished chip, and clean and dry it.

[0069] Polishing slurries include bonded magnetic abrasive polishing slurries and shear-thickened polishing slurries. Magnetic-bonded polishing slurries have a large abrasive particle size and are suitable for rough polishing in the early stages of processing. Shear-thickened polishing slurries (STF polishing slurries) have small abrasive particle size and are suitable for fine polishing in the middle and later stages of polishing.

[0070] The abrasive particle size in the magnetically bonded polishing slurry is approximately 70 μm, while the abrasive particle size in the shear-thickened polishing slurry is approximately 10 μm.

[0071] The preparation method of magnetic bonding polishing slurry includes the following steps:

[0072] T1. Take an iron matrix (carbonyl iron powder) and abrasive particles (alumina and silicon carbide) in a mass ratio of 9:1. Taking a total mass of 20g as an example, the proportions are 18g and 2g respectively. After thorough mixing, a uniform mixed powder is obtained.

[0073] T2. During the mixing process of the powder, gradually add the adhesive, i.e., 502 glue, at a rate of about 5% to 10% of the total mass of the powder, or about 1 to 2g, to ensure that the mixture is evenly bonded.

[0074] T3. Place the mixture in a constant temperature drying oven for curing at 60℃ for 2–4 hours;

[0075] T4. Remove the cured magnetic abrasive block, perform preliminary crushing, and place it in a cool, dry place to air dry;

[0076] T5. The crushed abrasive is sieved through a standard sorting sieve (80 mesh) to determine its particle size;

[0077] T6. The obtained bonding powder and silicone oil-based carrier liquid (Dowcon PMX-200 silicone oil) are mixed at a mass ratio of 1:1 to finally prepare the magnetic bonding polishing liquid.

[0078] The method for preparing the shear-thickening polishing fluid includes the following steps:

[0079] T1. Dissolve nano-silica particles in anhydrous ethanol medium; the anhydrous ethanol concentration is 99.9%, and approximately 10g of nano-silica particles are added to 300ml of anhydrous ethanol;

[0080] T2. Place the dispersed solution in a naturally ventilated environment to dry at room temperature;

[0081] T3. Grind the dried blocky silica into powder;

[0082] T4. Mix powdered nano-silica and organic dispersant PEG-200 at a mass ratio of 1:5 and mechanically stir to fully dissolve them to obtain the base liquid;

[0083] T5. Transfer the prepared base liquid to a vacuum device for vacuum treatment for 1 hour to eliminate air bubbles generated during mechanical stirring and obtain a transparent nano-silica-based shear thickening liquid;

[0084] T6. Add silicon carbide abrasive particles and carbonyl iron particles (CIPs) in a mass ratio of 1:9 to the nano-silica-based shear thickening liquid. The mass of the two powders accounts for 30% of the final polishing liquid concentration. For example, for 80g of polishing liquid, the mass of the two powders is 2.4g and 21.6g respectively. Repeat mechanical stirring and vacuum degassing treatment to finally prepare the nano-silica-based polishing liquid sample.

[0085] The principle of using polishing slurry to process chip microchannels is as follows: Under the action of a magnetic field, the magnetic abrasives (composite particles of silicon carbide or aluminum oxide held together by adhesive) in the polishing slurry, which fills the space between the magnetic poles and the component surface, form "grinding brushes" along the direction of the magnetic field lines. The magnetic particles (carbonyl iron powder) in the polishing slurry, under the influence of the magnetic field, drive the abrasive particles (silicon carbide or aluminum oxide) to apply a certain force to the component surface. When the "grinding brushes" and the magnetic poles move together, the abrasive particles in the "grinding brushes" and the component surface generate relative motion, thereby achieving a polishing effect on the component surface.

[0086] Silicon carbide or alumina abrasive particles are not magnetic. When they are mixed and bonded with carbonyl iron powder, magnetic composite particles are obtained.

[0087] Comparison of the polishing slurry in this application with traditional polishing slurries:

[0088] 1. Traditional polishing slurries lack binder components and are merely a physical mixture of abrasive and magnetic particles, resulting in weak bonding and easy precipitation. The magnetically bonded polishing slurry of this application uses glue to chemically bond abrasive particles (Al2O3 / SiC) and carbonyl iron powder into composite particles, resulting in a strong bond and no precipitation. The STF polishing slurry relies on a three-dimensional network of nano-silica, which "hardens" and dynamically locks the abrasive particles during vibration and shearing, preventing precipitation.

[0089] 2. Traditional polishing slurries lack a suspension mechanism, and the large differences in particle density make them prone to sedimentation and stratification. The magnetically bonded polishing slurry of this application reduces sedimentation and prevents agglomeration by adjusting the density of composite particles and selecting a lubricating oil base. The STF polishing slurry has optimal suspension properties due to the steric hindrance of the nano-network and does not settle over a long period of time.

[0090] 3. Traditional polishing slurries have a single, original particle size without targeted screening or dispersion treatment, and lack a dispersion stabilization mechanism. Van der Waals forces between abrasive grains lead to agglomeration, forming large particle agglomerates. The magnetic bonding polishing slurry of this application controls the particle size through "bonding-crushing-sieving", resulting in uniform and larger particle size (suitable for coarse polishing). The STF polishing slurry uses ultrafine abrasive grains + dispersant, and a nano-network to prevent agglomeration, resulting in fine and stable particle size (suitable for fine polishing).

[0091] To compare the polishing effects and usage of two polishing slurries (bonded abrasive polishing slurry and STF polishing slurry), microfluidic chips were polished using both slurries. The concentration of polishing powder and the ratio of abrasive powder to carbonyl iron powder remained consistent in both slurries; only the preparation method of the polishing powder was changed. For the magnetically bonded polishing slurry: its "polishing powder" consisted of "magnetic abrasive composite particles" obtained by pre-bonding abrasive powder and carbonyl iron powder together with glue, followed by crushing and sieving. For the shear-thickening polishing slurry: its "polishing powder" consisted of abrasive powder and carbonyl iron powder as two separate, unbonded powders, directly dispersed into the STF base liquid.

[0092] Figure 7 This is a photograph of the magnetic bonding polishing slurry prepared according to the present invention. Figure 8 This is a photograph of the shear-thickening polishing fluid prepared according to the present invention. Figure 9 These are comparison images of the microchannel surface morphology of the microfluidic chip prepared according to the present invention before polishing (left image) and after polishing (right image). Figure 10 These are comparison images of the transparency of the microfluidic chip prepared according to this invention before polishing (left image) and after polishing (right image). Figure 11Comparison of cell staining images under an inverted fluorescence microscope before and after polishing of the microfluidic chip prepared for this invention (left image) and after polishing (right image) when used for cell culture.

[0093] The surface roughness of samples processed by the two polishing slurries changed with polishing time as follows: Figure 12 As shown in the figure, the polishing rate of the magnetically bonded polishing slurry is relatively fast, reaching its polishing limit in 20-30 minutes, reducing the sample surface roughness from 1.1 μm to 0.2 μm. However, due to the larger abrasive particles, prolonged polishing can damage the sample surface. With STF polishing slurry, due to the precipitation of abrasive powder during polishing, compared to magnetically bonded powder (i.e., particles pre-composite to carbonyl iron powder by a binder), carbonyl iron powder of the same particle size requires smaller abrasive particles to prevent precipitation. Therefore, when using STF polishing, the surface roughness of the sample decreases more slowly; after 50 minutes of polishing, the surface roughness decreased from 0.97 μm to approximately 0.3 μm. In summary, the magnetically bonded polishing slurry, with its large abrasive particle size, is suitable for initial rough polishing to quickly remove surface protrusions. The STF polishing slurry, with its small abrasive particle size, is suitable for later-stage fine polishing to further reduce surface roughness and improve surface quality.

[0094] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A microchannel polishing device for 3D printed microfluidic chips, characterized in that, include: A motion control component, wherein the motion control component is provided with a fixture for placing a chip; A vibration platform, located below the motion control assembly; A connector, which is fixedly mounted on the vibration platform; A polishing head is mounted on a connector and corresponds to a fixture. The polishing head includes an excitation module and a magnetic pole module and is placed in a stable magnetic field.

2. The microchannel polishing device for 3D printed microfluidic chips according to claim 1, characterized in that, The motion control component is a three-dimensional motion platform, including an X-axis motion component, a Y-axis motion component and a Z-axis motion component, with the fixture mounted on the Z-axis motion component.

3. The microchannel polishing apparatus for 3D printed microfluidic chips according to claim 1, characterized in that, The vibration platform is horizontally positioned below the motion control component. The connector is a 3D-printed polymer material connector, which is L-shaped. The magnetic pole module and the excitation module are positioned opposite each other on the connector, with the magnetic pole module located above the excitation module. The magnetic pole module and the excitation module correspond to the fixtures on the motion control component.

4. The microchannel polishing apparatus for 3D printed microfluidic chips according to claim 1, characterized in that, The excitation module includes a large permanent magnet fixed on the connector and a small permanent magnet located above the large permanent magnet. Both the small permanent magnet and the large permanent magnet are cylindrical. The magnetic pole module is a pure iron rod, which is installed vertically on the upper part of the connector.

5. The microchannel polishing apparatus for 3D printed microfluidic chips according to claim 4, characterized in that, Both the large and small permanent magnets are neodymium iron boron magnets. The large permanent magnet has a diameter of 30 mm and a height of 30 mm, and is made of N52 material. The small permanent magnet has a diameter of 10 mm and a height of 10 mm, and is also made of N52 material.

6. The microchannel polishing apparatus for 3D printed microfluidic chips according to claim 1, characterized in that, The vibration platform is a rectangular plate with multiple through holes on its surface. It is part of a small precision vibration testing system and is connected to an exciter and a sensor.

7. A method for polishing using the microchannel polishing apparatus for 3D-printed microfluidic chips according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Place the 3D printed chip to be polished on the fixture and make precise adjustments using the motion control components to center it in the polishing area; S2. Based on the chip's material and surface condition, set appropriate parameters such as magnetic field strength, vibration frequency, and polishing time using the vibration platform's software. When the vibration platform moves, the sensor monitors the motion parameters in real time. S3. Before polishing, the polishing slurry is injected into the microchannels of the 3D printed chip to be polished. For 3D printed chips with semi-closed channel structures, the polishing slurry is directly injected into the position to be polished. For closed 3D printed chips, the polishing slurry can be injected into the microchannels of the 3D printed chip through the chip inlet in advance using a syringe. S4. Start the excitation module and motion control component. Use the motion control component to control the polishing head so that the polishing fluid performs precision micro-cutting and polishing on the chip surface under the action of the magnetic field. S5. After polishing is complete, shut down the system, remove the polished chip, and clean and dry it.

8. The polishing method using a microchannel polishing device with a 3D-printed microfluidic chip according to claim 7, characterized in that, The polishing fluid in S3 includes a bonding magnetic abrasive polishing fluid and a shear-thickened polishing fluid, wherein the preparation method of the magnetic bonding polishing fluid includes the following steps: T1. Take iron matrix and abrasive grains in a mass ratio of 9:1, mix them thoroughly to obtain a uniform mixed powder; T2. During the mixing process of the powder, gradually add the adhesive, i.e., 502 glue. The amount of adhesive added is about 5% to 10% of the total mass of the powder to ensure that the mixture is evenly bonded. T3. Place the mixture in a constant temperature drying oven for curing at 60℃ for 2–4 hours; T4. Remove the cured magnetic abrasive block, perform preliminary crushing, and place it in a cool, dry place to air dry; T5. The pulverized abrasive is sieved for particle size separation using a standard sorting sieve; T6. The obtained bonding powder and silicone oil-based carrier liquid are mixed at a mass ratio of 1:1 to finally prepare the magnetic bonding polishing liquid.

9. The polishing method using a microchannel polishing device with a 3D-printed microfluidic chip according to claim 8, characterized in that, The method for preparing the shear-thickening polishing fluid includes the following steps: T1. Dissolve the nano-silica particles in anhydrous ethanol medium until the powder is submerged. For example, add about 300ml of anhydrous ethanol to 10g of nano-silica particles. T2. Place the dispersed solution in a naturally ventilated environment to dry at room temperature; T3. Grind the dried blocky silica into powder; T4. Mix powdered nano-silica and organic dispersant PEG-200 at a mass ratio of 1:5 and mechanically stir to fully dissolve them to obtain the base liquid; T5. Transfer the prepared base liquid to a vacuum device for vacuum treatment for 1 hour to eliminate air bubbles generated during mechanical stirring and obtain a transparent nano-silica-based shear thickening liquid; T6. Silicon carbide abrasive particles and carbonyl iron particles (CIPs) were added sequentially to the nano-silica-based shear thickening liquid, and mechanical stirring and vacuum degassing were repeated to finally prepare a nano-silica-based polishing liquid sample.

10. An application of a 3D printed chip prepared using the polishing method of claim 7 in biomedicine.

Images