Flexible roll forming method of micro-channel structure for bioreactor

Abstract

The invention discloses a flexible roll forming method of a micro-channel structure for a bioreactor. The flexible roll forming method comprises the following steps: step 1, designing characteristic roll teeth according to the thickness, depth-to-width ratio and spacing of the formed micro-channel structure; 2, a polyurethane flexible pad with the specific thickness and hardness is selected and placed at the feeding position of a rolling device, and the pretreated foil is placed on the polyurethane flexible pad; 3, setting the amplitude and frequency of the ultrasonic vibration device; fourthly, the rolling speed and pressure are set; and fifthly, the device is started, and forming is conducted. The method is suitable for high-efficiency, high-precision and zero-breakage-rate forming of the micro-channel structure for the bioreactor.

Description

Technical Field

[0001] The present invention relates to an advanced manufacturing technology for improving the manufacturing yield, efficiency and service life of a microfluidic structure, and in particular to a flexible roll forming method for a microfluidic structure for a bioreactor. Background Art

[0002] Microbial reactors are widely used in the fields of chemical industry, medicine, and biological fermentation. The principle is to allow the reaction raw materials to flow at high speed through microchannels with sizes ranging from micrometers to millimeters. As core components, microchannel structures must meet stringent requirements such as large specific surface area, high specific strength, low residual stress, and low microscopic damage. Existing processing methods for microchannel structures are micro-milling and electrolysis, which are expensive, low in productivity, and have large residual stress. The flexible rolling forming method of a microchannel structure for a bioreactor proposed in the present invention has the following characteristics: (1) Using an ultrasonic vibration field to reduce the influence of the size effect, promote the participation of individual grain heterogeneous grains in deformation, and the microscopic feature forming quality of the microchannel structure is very good with low residual stress. (2) Using a flexible pad can effectively avoid the rupture of the ultra-thin wall microchannel structure and improve the yield and service life of the microchannel structure. (3) For other types of microchannel structures, only the characteristic roller teeth need to be replaced, and the process and equipment are highly flexible. (4) The surface quality of the microchannel structure is high, which can greatly improve the flow, chemical reaction and heat dissipation effects. (5) The roller pressing process enables continuous production with high efficiency and low unit cost.

[0003] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0004] The purpose of the present invention is to provide a flexible roll forming method for a microfluidic structure for a bioreactor, which can (1) apply a specific ultrasonic vibration field to a stainless steel foil having a certain microstructure to produce an acoustic softening effect, promote the rotation and deformation of heterogeneous grains in the foil, and promote the forming of the microstructure; (2) use ultrasonic vibration to promote the high-speed and trace migration of a flexible pad into the microstructure, thereby improving the strength and forming accuracy of the microstructure; (3) use only one roller tooth with a characteristic microstructure to achieve precise forming of microfluidic structures with different aspect ratios, and use different thicknesses and hardnesses of the flexible pad to achieve different aspect ratios of the microfluidic structure, thereby improving the forming flexibility.

[0005] To achieve the above object, an embodiment of the present invention provides a flexible roll forming method for a microfluidic channel structure for a bioreactor, characterized in that it comprises the following steps:

[0006] Step 1: According to the wall thickness of the microchannel structure of 5 to 200 μm, the groove width of 300 to 5000 μm, and the aspect ratio of 0.2 to 1.5, a characteristic roller tooth with a groove width of 330 to 5500 μm, an aspect ratio of 0.22 to 1.65, a tooth fillet radius of 0.1 to 0.2 mm, a spacing of 500 to 2000 μm, and an array quantity of 1 to 30 is designed;

[0007] Step 2: Then place a polyurethane flexible pad with a Shore hardness of A50-90 and a thickness of 1-10 mm at the feed inlet of the roller pressing device, and place the pretreated stainless steel foil on the flexible pad;

[0008] Step 3: setting the frequency of ultrasonic vibration to 5-30 kHz and the amplitude to 5-30 μm, and the ultrasonic vibration acts on the flat circular roller in a radial emission mode;

[0009] Step 4: Set the downward pressure of the characteristic roller teeth to 50-3000N, and set the rotation speed of the flat round roller to 1-50mm / s.

[0010] Step 5: Start the device and begin rolling.

[0011] In one or more embodiments of the present invention, the foil pretreatment in step 2 is to stretch the stainless steel foil by 1-5% along the rolling direction, then keep it at 700-900°C for 2h, and then oil quench it at 0-50°C.

[0012] In one or more embodiments of the present invention, the ultrasonic vibration described in step three acts on the characteristic roller teeth in an axially telescopic manner, and the frequency of the ultrasonic vibration is 15-20 kHz and the amplitude is 5-10 μm.

[0013] In one or more embodiments of the present invention, the rolling device described in step 2 includes four modules: a roll tooth module, an ultrasonic vibration module, a pressure module, and an intelligent control module; the roll tooth module includes characteristic roll teeth and a plane round roller; the ultrasonic vibration module includes a plane round roller radial vibration system and a characteristic roll tooth axial vibration system; the pressure module includes an air compressor, a cylinder and a guide rail, and the cylinder applies pressure to the characteristic roll teeth through a retaining frame; the intelligent control module includes a servo motor and a control panel, and the servo motor transmits power to the plane round roller through a coupling.

[0014] Compared with the prior art, the new process proposed by the present invention can overcome the problems of size effect, easy breakage, low efficiency and low mold adhesion in microfluidic forming, and has the following advantages: 1. The coupling effect of ultrasonic excitation and microscopic crystal defects promotes the deformation of individual heterogeneous grains and eliminates the influence of size effect. 2. The free deformation of the flexible pad promotes the microstructure to adhere to the mold and improves the forming accuracy. 3. The flexible pad with specific hardness and thickness can be combined with the pressure of the roller teeth to adjust the forming depth of the microfluidic structure. 4. Ultrasonic vibration can excite the soft mold to effectively reduce the forming force, reduce the metal flow stress, and reduce the friction between the workpiece and the mold. Flexible roller forming can handle more complex and finer workpiece shapes and meet higher production requirements. Therefore, the method of the present invention is particularly suitable for the efficient, high-quality and controllable manufacturing of microfluidic structures for bioreactors. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a comparison diagram of a flexible roll forming method for a microfluidic channel structure for a bioreactor according to an embodiment of the present invention and a conventional method;

[0016] Figure 2 is a schematic diagram of a rolling device according to an embodiment of the present invention;

[0017] Explanation of the numbers in the figure: 1. Roller tooth module, 101. Characteristic roller tooth, 102. Flat round roller, 2. Ultrasonic vibration module, 201. Radial vibration system, 202. Axial vibration system, 3. Polyurethane flexible pad, 4. Stainless steel foil, 5. Microchannel structure, 6. Pressure module, 601. Cylinder, 602. Air compressor, 603. Guide rail, 604. Cage, 7. Intelligent control module, 701. Servo motor, 702. Control panel, 703. Servo coupling. DETAILED DESCRIPTION

[0018] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0019] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0020] According to a preferred embodiment of the present invention, a flexible roll forming method for a microfluidic channel structure for a bioreactor is specifically implemented as follows:

[0021] Step 1: According to the wall thickness of the formed microfluidic channel structure 5 of 5-200 μm, the groove width of 300-5000 μm, the aspect ratio of 0.2-1.5, the characteristic roller teeth 101 with a groove width of 330-5500 μm, a depth-to-width ratio of 0.22-1.65, a tooth fillet radius of 0.1-0.2 mm, a spacing of 500-2000 μm, and an array quantity of 1-30 are designed;

[0022] Step 2: Then place a polyurethane flexible pad 3 with a Shore hardness of A50-90 and a thickness of 1-10 mm at the feed inlet of the rolling device, and place the pretreated stainless steel foil 4 on the polyurethane flexible pad 3;

[0023] Step 3: setting the frequency of ultrasonic vibration to 5-30 kHz and the amplitude to 5-30 μm, and the ultrasonic vibration acts on the flat circular roller 102 in a radial emission manner;

[0024] Step 4: Set the downward pressure of the characteristic roller teeth 101 to 50-3000N, and set the rotation speed of the flat round roller 102 to 1-50mm / s.

[0025] Step 5: Start the device and begin rolling.

[0026] Example 1

[0027] Taking the preparation of 100 stainless steel microfluidic channel structures with a length of 200 mm, a width of 30 mm, a groove width of 500 μm, a depth-to-width ratio of 0.5, a thickness of 100 μm, and an array quantity of 20 as an example, the implementation process of the method of the present invention for preparing an ultra-thin-wall microfluidic channel structure is described as follows:

[0028] A stainless steel foil with a width of 30 mm, a length of 200 mm, and a thickness of 100 μm was stretched 3% in the rolling direction in advance, then kept at 850° C. for 2 h, and then oil quenched at 30° C.

[0029] Step 1: Design a characteristic roller tooth with a groove width of 550 μm, an aspect ratio of 0.55, a tooth fillet radius of 0.1 mm, a spacing of 500 μm, and an array quantity of 20;

[0030] Step 2: Then place a polyurethane flexible pad with a Shore hardness of A70 and a thickness of 10 mm at the feed inlet of the roller pressing device, and place the pretreated stainless steel foil on the flexible pad;

[0031] Step 3: Set the frequency of ultrasonic vibration to 20kHz and the amplitude to 20μm, and the ultrasonic vibration acts on the flat circular roller in a radial emission mode;

[0032] Step 4: Set the downward force of the characteristic roller teeth to 500N and the rotation speed of the flat round roller to 30mm / s.

[0033] Step 5: Start the device and begin rolling.

[0034] Comparative Example 1

[0035] Using the traditional stamping method, 100 pieces of stainless steel microfluidic structure were prepared. The steps are as follows:

[0036] Step 1: Clean the stainless steel foil with a width of 30 mm, a length of 200 mm, and a thickness of 100 μm;

[0037] Step 2: Design a pair of male and female molds according to the microchannel structure, and press them with a 50-ton press;

[0038] Step 3: Position the foil on the die, start the press to move downward, complete the stamping and hold the pressure for 30 seconds;

[0039] Step 4: Pick up and inspect.

[0040] Comparison results

[0041] Table 1 Comparison between the method of the present invention and the traditional method

[0042]

[0043] The present invention proposes a flexible roll forming method for a microfluidic structure for a bioreactor. According to the microstructure and thickness of the foil, a flexible pad of suitable hardness and thickness is selected, and specific ultrasonic vibration parameters, compressive stress state and roll forming speed are set. The downward pressure of the characteristic roller teeth can be adjusted, and the change of the downward pressure further changes the depth-to-width ratio of the microfluidic structure. The flexible pad can dynamically compensate for the slight deviation of the master and slave roller tooth axes, and greatly eliminate the forming distortion and cracking defects. Under the action of ultrasonic vibration, the foil greatly absorbs the energy of ultrasonic vibration, the dislocation kinetic energy is greatly increased, and some hard-oriented grains rotate and deform under the action of impact vibration, and the forming uniformity and plasticity of the foil are greatly improved. Therefore, as shown in Table 1, the method of the present invention greatly improves the flexibility of forming, and the dimensional accuracy and strength of the product are greatly improved compared with the traditional method.

[0044] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A flexible roll forming method for a microfluidic channel structure for a bioreactor, characterized in that: The following steps are involved: Step 1: According to the wall thickness of the microchannel structure of 5 to 200 μm, the groove width of 300 to 5000 μm, and the aspect ratio of 0.2 to 1.5, a characteristic roller tooth with a groove width of 330 to 5500 μm, an aspect ratio of 0.22 to 1.65, a tooth fillet radius of 0.1 to 0.2 mm, a spacing of 500 to 2000 μm, and an array quantity of 1 to 30 is designed; Step 2: Then place a polyurethane flexible pad with a Shore hardness of A50-90 and a thickness of 1-10 mm at the feed inlet of the roller pressing device, and place the pretreated stainless steel foil on the flexible pad; Step 3: setting the frequency of ultrasonic vibration to 5-30 kHz and the amplitude to 5-30 μm, and the ultrasonic vibration acts on the flat circular roller in a radial emission mode; Step 4: Set the downward pressure of the characteristic roller teeth to 50-3000N, and set the rotation speed of the flat round roller to 1-50mm / s. Step 5: Start the device and begin rolling.

2. A flexible roll forming method for a microfluidic channel structure for a bioreactor according to claim 1, characterized in that: The foil pretreatment described in step 2 is to stretch the stainless steel foil along the rolling direction by 1-5%, then keep it at 700-900°C for 2h, and then oil quench it at 0-50°C.

3. The flexible roll forming method of a microfluidic channel structure for a bioreactor according to claim 1, characterized in that: The ultrasonic vibration described in step three acts on the characteristic roller teeth in an axially telescopic manner, and the frequency of the ultrasonic vibration is 15 to 20 kHz and the amplitude is 5 to 10 μm.

4. The flexible roll forming method of a microfluidic channel structure for a bioreactor according to claim 1, characterized in that: The rolling device described in step 2 includes four modules: a roll tooth module, an ultrasonic vibration module, a pressure module, and an intelligent control module; the roll tooth module includes characteristic roll teeth and a plane round roller; the ultrasonic vibration module contains a plane round roller radial vibration system and a characteristic roll tooth axial vibration system; the pressure module includes an air compressor, a cylinder and a guide rail, and the cylinder applies pressure to the characteristic roll teeth through a retaining frame; the intelligent control module includes a servo motor and a control panel, and the servo motor transmits power to the plane round roller through a coupling.

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