Processing method of surface anti-icing microstructure

Abstract

The invention belongs to the field of surface icing resistance of metal materials, and particularly relates to a machining method of a surface icing-resistant microstructure. The anti-icing structure is prepared on the 30CrMnSiNi2A surface by using micro-milling and surface modification technologies, the operation is simple, the cost is low, the processing efficiency is higher, and the preparation of a large-area anti-icing surface of a material is expected to be realized. And meanwhile, the method is also suitable for preparing anti-icing structure surfaces of other materials. Atmospheric pressure cold plasma jet is adopted, localized modification is conducted on the material surface through the Rehbinder effect, and the machining quality and machining efficiency of the anti-icing structure are improved. And the modified surface is cut in time, so that the material characteristics of the anti-icing surface are not influenced, and the influence on the service performance of the material is avoided. The device is simple and easy to operate, small in space size and high in adaptability, when the device is used, only the plasma spray head needs to be aligned with a machining area, additional modification does not need to be conducted on a machine tool, and the production cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of anti-icing on the surface of metal materials, and particularly relates to a processing method for a surface anti-icing microstructure. Background Art

[0002] As an important high-performance alloy, 30CrMnSiNi2A high-strength steel is widely used in fields such as shipbuilding, military equipment, and aerospace due to its high strength, high toughness, and good wear resistance. In addition, with the rapid development of science and technology and industrial manufacturing, higher requirements are put forward for the processing technology and service environment of 30CrMnSiNi2A parts. For example, in a low-temperature environment, ice nuclei will quickly form on the surface of 30CrMnSiNi2A material, which seriously affects its normal use and even causes catastrophic accidents.

[0003] In engineering applications, mechanical or heating methods are mainly used for de-icing. However, these passive de-icing methods often require a large amount of energy and have low efficiency. Therefore, there is an urgent need for a surface with an active anti-icing structure to delay icing. The superhydrophobic surface is not only widely used in fields such as self-cleaning and oil-water separation, but also shows excellent performance in the anti-icing field. Therefore, constructing a superhydrophobic structure on the material surface has become the main technical solution for preparing an anti-icing surface. At present, most of the methods for preparing a superhydrophobic surface are to etch the material surface and coat a superhydrophobic coating, but these methods have low processing efficiency and high cost, and it is difficult to meet the requirements of large-area preparation. Summary of the Invention

[0004] Micro-milling technology can process high-quality microstructures at a relatively low production cost and has high production efficiency. However, during the micro-milling process of 30CrMnSiNi2A high-strength steel, affected by its excellent mechanical properties, large cutting forces and severe cutting deformation are easily generated, resulting in serious tool wear and poor machining surface quality. The atmospheric pressure cold plasma jet contains a large number of active particles and has a low macroscopic temperature. The active particles rich in the jet induce the Rehbinder effect on the workpiece surface, promote the crack propagation and ductile fracture on the workpiece surface, reduce the plastic deformation resistance of the material, and then reduce the cutting force and cutting deformation during the processing, realizing high-quality and high-efficiency processing of the material. Therefore, the present invention proposes a method of using an atmospheric pressure cold plasma jet-assisted micro-milling to prepare an anti-icing structure on the surface of 30CrMnSiNi2A material. At present, there is no report on this method of using an atmospheric pressure cold plasma jet to regulate the material properties of 30CrMnSiNi2A high-strength steel to achieve high-quality and high-efficiency processing of the anti-icing structure surface.

[0005] The present invention aims to solve the problem that the existing anti-icing surface preparation process is difficult to meet the requirements of large-area preparation, and provides a structure for realizing anti-icing on the surface of 30CrMnSiNi2A material and its preparation method, that is, microstructures are machined on the surface of 30CrMnSiNi2A by micro-milling technology to achieve the anti-icing effect. At the same time, a cold plasma jet is introduced during the micro-milling process, and the Rehbinder effect is used to promote material fracture and inhibit plastic flow, thereby reducing the cutting force and cutting deformation, and improving the machining quality and efficiency of the anti-icing structure. This method has the characteristics of simple equipment, wide applicability, simple operation and environmental friendliness.

[0006] According to one aspect of the present application, a processing method for a surface anti-icing microstructure is provided to realize the anti-icing microstructure on the surface of 30CrMnSiNi2A material. First, micro-grooves and micro-columns are machined on the smooth surface of 30CrMnSiNi2A by micro-milling technology to accommodate the gas film, and then the surface of the structure is modified with a low surface energy substance to achieve the effect of delaying icing.

[0007] A micro-milling device for processing the surface anti-icing microstructure is adopted;

[0008] The surface anti-icing microstructure is a micro-groove structure and / or a micro-column structure;

[0009] For the micro-groove structure, the ridge width d = 200 μm, the groove width w = 500 μm, and the groove depth h = 600 μm;

[0010] For the micro-column structure, the column width d = 500 μm, the groove width w = 500 μm, and the groove depth h = 600 μm;

[0011] The micro-milling device consists of an atmospheric pressure cold plasma jet generating device and a processing machine tool;

[0012] The atmospheric pressure cold plasma jet generating device includes a working gas source 1, a pressure reducing valve 2, a flow meter 3, a discharge nozzle 4, and a working power supply 9;

[0013] The processing machine tool includes a cutting tool 6 and a working machine tool 8;

[0014] It includes the following steps:

[0015] The workpiece 7 is cut, ground, polished, and cleaned to determine the machining area of the workpiece 7; the workpiece 7 is clamped on the working machine tool 8, the discharge nozzle 4 and the cutting tool 6 are aligned with the machining area of the workpiece 7 for machining, and a micro-groove structure and / or a micro-column structure are machined in the machining area of the workpiece 7, ultrasonically cleaned, dried, the workpiece 7 is immersed in a low surface energy substance, and dried to obtain the surface anti-icing microstructure.

[0016] The working gas source 1 adjusts the gas pressure and flow rate through a pressure reducing valve 2 and a flow meter 3, and transports the gas to the discharge nozzle 4. The output end of the working power supply 9 is connected to the corresponding electrode of the discharge nozzle 4. When the gas is introduced into the discharge nozzle 4, a discharge voltage and frequency are applied to generate a stable light purple cold plasma jet 5, realizing real-time modification of the position to be processed.

[0017] The working machine tool 8 is used to clamp the workpiece 7 to be processed;

[0018] The tool 6 is aligned with the area to be processed of the workpiece 7 and cooperates with the cold plasma jet 5 to process the workpiece 7.

[0019] The parameters of the working machine tool 8 are as follows:

[0020] The spindle speed n of the machine tool is 20000 rpm to 50000 rpm;

[0021] The feed rate Vf is 200 μm / s to 1100 μm / s;

[0022] The cutting depth ap is 5 μm to 20 μm.

[0023] The parameters of the cold plasma jet 5 are as follows:

[0024] The gas pressure P is 0.4 MPa to 0.6 MPa;

[0025] The gas flow rate Q is 8 L / min to 12 L / min;

[0026] The discharge voltage U is 2 kV to 3 kV;

[0027] The frequency f is 50 kHz to 60 kHz.

[0028] The angle α between the discharge nozzle 4 and the horizontal plane is 30° to 60°, and is parallel to the feed direction of the tool 6.

[0029] The low surface energy substance is selected from at least one of an ethanol solution of fluorosilane, an ethanol solution of octadecyltrichlorosilane, or an ethanol solution of polydimethylsiloxane.

[0030] The concentration of the ethanol solution of fluorosilane is 0.5 to 2 wt%;

[0031] The concentration of the ethanol solution of octadecyltrichlorosilane is 1 to 3 wt%;

[0032] The concentration of the ethanol solution of polydimethylsiloxane is 1 to 10 wt%.

[0033] The working gas source 1 of the atmospheric pressure cold plasma jet generating device is selected from at least one of nitrogen, argon, helium, water vapor, oxygen, and filtered and dried air.

[0034] The working power supply 9 of the atmospheric pressure cold plasma jet generating device is any one of a DC high-voltage power supply, a low-frequency high-voltage power supply, a radio-frequency high-voltage power supply, a microwave high-voltage power supply, or a pulsed high-voltage power supply that can generate plasma.

[0035] The discharge nozzle 4 of the atmospheric pressure cold plasma jet adopts the form of bare electrode discharge, where a tungsten needle serves as the high-voltage electrode and a copper nozzle serves as the low-voltage electrode.

[0036] The immersion in the low surface energy substance is the low surface energy substance modification, specifically by soaking the surface of the microgroove and microcolumn structure with the low surface energy substance liquid for 40 min and heating and drying at 80 °C for 30 min.

[0037] The temperature of the cold plasma jet 5 is 20 °C to 35 °C. The lower macroscopic temperature can avoid the influence of temperature on the machining accuracy of the workpiece surface and also avoid heat damage problems such as surface phase transformation of the workpiece caused by too high temperature.

[0038] The atmospheric pressure cold plasma jet assisted micro-milling can not only be used for the preparation of the anti-icing structure of 30CrMnSiNi2A high-strength steel, but also be applicable to the preparation of the anti-icing structures of other materials.

[0039] Post-processing work: Turn off the plasma working power supply 9 and the gas source 1 in sequence, release the residual gas in the gas pipeline, then turn off the flowmeter 3, and remove the plasma nozzle 4; withdraw the tool 6, and perform the disassembly of the workpiece and the initialization of the machine tool.

[0040] Specifically, it includes the following steps:

[0041] Step 1: Select 30CrMnSiNi2A high-strength steel bar as the test raw material, obtain a workpiece with appropriate dimensions after wire electrical discharge machining, and polish it to a smooth surface. Then place the polished workpiece in absolute ethanol for ultrasonic cleaning.

[0042] Step 2: Use the atmospheric pressure cold plasma jet assisted micro-milling device to micro-mill the surface of the polished 30CrMnSiNi2A material to obtain a microgroove and microcolumn structure.

[0043] Step 3: Place the surface of the microgroove and microcolumn structure in absolute ethanol for ultrasonic cleaning and dry it with an air gun.

[0044] Step 4: Modify the surface of the cleaned and dried microgroove and microcolumn structure with a low surface energy substance to prepare a structure surface with anti-icing function.

[0045] The ultrasonic cleaning time is 1 min to 2 min.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] 1. The present invention uses micro-milling technology and surface modification technology to prepare an anti-icing structure on the surface of 30CrMnSiNi2A. The operation is simple, the cost is low, and the processing efficiency is high. It is expected to realize the preparation of a large-area anti-icing surface for materials. At the same time, this technical solution is also applicable to the preparation of anti-icing structure surfaces of other materials.

[0048] 2. The atmospheric pressure cold plasma jet adopted by the present invention can perform local modification on the material surface through the Rehbinder effect, improving the processing quality and efficiency of the anti-icing structure. The modified surface is cut in time, so it will not affect the material properties of the anti-icing surface, avoiding the influence on the service performance of the material.

[0049] 3. The atmospheric pressure cold plasma jet generating device is simple in equipment, easy to operate, has a small space volume and high adaptability. When in use, only the plasma nozzle needs to be aligned with the processing area, and no additional modification of the machine tool is required, reducing the production cost. Description of the Drawings

[0050] Figure 1 It is a schematic diagram of a micro-milling device for processing surface anti-icing microstructures; wherein, 1 is the working gas source; 2 is the pressure reducing valve; 3 is the flow meter; 4 is the discharge nozzle; 5 is the cold plasma jet; 6 is the tool; 7 is the workpiece; 8 is the processing machine tool; 9 is the working power supply;

[0051] Figure 2 It is a comparison chart of the cutting forces in all directions for milling micro-groove structures under different working conditions;

[0052] Figure 3 It is a comparison chart of the surface roughness for milling micro-groove structures under different working conditions;

[0053] Figure 4 It is a size and structure schematic diagram of the micro-groove structure and the micro-column structure, wherein, a is the micro-groove structure and b is the micro-column structure;

[0054] Figure 5 It is a comparison chart of surface icing, wherein, a is the unprocessed surface, b is the micro-groove structure surface, and c is the micro-column structure surface. Detailed Embodiments

[0055] The following describes the present application in detail with reference to the embodiments, but the present application is not limited to these embodiments.

[0056] Embodiment 1

[0057] This embodiment relates to a microgroove structure for realizing ice resistance on the surface of 30CrMnSiNi2A material and a preparation method thereof. The specific implementation steps are as follows:

[0058] (1) Preparation of the processed material: Select a Φ45mm 30CrMnSiNi2A high-strength steel bar as the test raw material. After wire electrical discharge machining, a square workpiece 7 with dimensions of 15mm×15mm×3mm is obtained, and it is polished until the surface is smooth. Then, the polished workpiece 7 is placed in absolute ethanol for ultrasonic cleaning;

[0059] (2) Clamping of the workpiece and the tool: Install the workpiece 7 to be processed on the processing machine tool 8, and perform clamping and tool setting. The tool 6 uses a tungsten carbide two-edge flat-bottom milling cutter with a diameter of Φ0.5mm;

[0060] (3) Debugging of the atmospheric pressure cold plasma jet generating device: Connect Figure 1 the gas pipeline and the circuit in it, and sequentially turn on the plasma working gas source 1, the pressure reducing valve 2, and the flowmeter 3. Then, turn on the plasma working power supply 9 and adjust parameters such as voltage and frequency. To ensure the generation of a stable cold plasma jet 5 with a certain length, the gas pressure P = 0.4MPa, the gas flow rate Q = 12L / min, the discharge voltage U = 2.5kV, and the frequency f = 58.6kHz.

[0061] (4) Installation of the cold plasma jet nozzle: Install the nozzle 4 of the cold plasma jet on the machine tool 8, and adjust the inclination angle of the nozzle 4 so that it is aligned with the tool-workpiece cutting interface. The angle α between the nozzle 4 and the horizontal plane is 45°, and it is parallel to the feed direction of the tool 6.

[0062] (5) Machining of the ice-resistant microgroove structure surface: Input the set cutting parameters into the controller of the processing machine tool 8, and perform assisted micro-milling machining with the cold plasma jet. After the machining of the microgroove structure surface is completed, it is placed in absolute ethanol for ultrasonic cleaning and dried with an air gun. The surface of the ice-resistant microgroove structure adopts a combination of rough machining and finish machining. The milling parameters for rough machining are: spindle speed n = 40000rpm, feed rate Vf = 500μm / s, and cutting depth ap = 20μm. The milling parameters for finish machining are: spindle speed n = 40000rpm, feed rate Vf = 800μm / s, and cutting depth ap = 5μm.

[0063] (6) Modification with low surface energy substances: Immerse the surface of the microgroove structure with a ridge width d = 200μm, a groove width w = 500μm, and a groove depth h = 600μm obtained in step (5) in a 1mmol / L ethanol solution of fluorosilane for 40min, and heat and dry it at 80°C for 30min. Finally, an ice-resistant surface with a microgroove structure is prepared, and the water contact angle is 154.5°.

[0064] Using the polished ordinary surface as the control group, a delayed icing test was carried out on the ordinary surface and the micro-groove structure surface at -10°C using a cold stage. Figure 5 The test results in show that the ordinary surface was completely frozen at 22 s, while the icing time of the surface with the micro-groove structure could be extended to 231 s.

[0065] Example 2

[0066] This example relates to a micro-column structure for realizing anti-icing on the surface of 30CrMnSiNi2A material and its preparation method. The specific implementation steps are as follows:

[0067] (1) Preparation work of the processed material: Select a Φ45mm 30CrMnSiNi2A high-strength steel bar as the test raw material. After wire electrical discharge machining, a square workpiece 7 with dimensions of 15mm×15mm×3mm is obtained, and it is polished until the surface is smooth. Then, the polished workpiece 7 is placed in absolute ethanol for ultrasonic cleaning.

[0068] (2) Clamping of the workpiece and the tool: Install the workpiece 7 to be processed on the processing machine tool 8, and perform clamping and tool setting. The tool 6 uses a tungsten carbide double-edge flat-end milling cutter with a diameter of Φ0.5mm.

[0069] (3) Debugging of the atmospheric pressure cold plasma jet generating device: Connect the Figure 1 gas pipeline and circuit in , and sequentially turn on the plasma working gas source 1, pressure reducing valve 2, and flowmeter 3. Then, turn on the plasma working power supply 9 and adjust parameters such as voltage and frequency. To ensure the generation of a stable and cold plasma jet 5 with a certain length, the gas pressure P = 0.4 MPa, the gas flow rate Q = 12 L / min, the discharge voltage U = 2.5 kV, and the frequency f = 58.6 kHz.

[0070] (4) Installation of the cold plasma jet nozzle: Install the nozzle 4 of the cold plasma jet on the machine tool 8, and adjust the inclination angle of the nozzle 4 so that it is aligned with the tool-workpiece cutting interface. The angle α between the nozzle 4 and the horizontal plane is 45°, and it is parallel to the feed direction of the tool 6.

[0071] (5) Processing of the surface of the anti-icing micro-column structure: Input the set cutting parameters into the controller of the processing machine tool 8, and perform assisted micro-milling with a cold plasma jet. After the surface of the micro-column structure is processed, it is ultrasonically cleaned in anhydrous ethanol and dried with an air gun. The surface of the anti-icing micro-column structure adopts a combination of rough machining and finish machining. The milling parameters for rough machining are: spindle speed n = 40,000 rpm, feed rate Vf = 500 μm / s, and cutting depth ap = 20 μm. The milling parameters for finish machining are: spindle speed n = 40,000 rpm, feed rate Vf = 800 μm / s, and cutting depth ap = 5 μm.

[0072] (6) Modification with low-surface-energy substances: Immerse the surface of the micro-column structure with a column width d = 500 μm, groove width w = 500 μm, and groove depth h = 600 μm obtained in step (5) in a 1 mmol / L ethanol solution of fluorosilane for 40 min, and heat and dry it at 80 °C for 30 min. Finally, an anti-icing surface with a micro-column structure is prepared, and the water contact angle is 151.5°.

[0073] Taking the polished ordinary surface as the control group, a delayed icing test was carried out on the ordinary surface and the micro-column structure surface at -10 °C using a cold stage. Figure 5 The test results in [reference] show that the ordinary surface was completely frozen at 22 s, while the icing time of the surface with a micro-column structure could be extended to 1431 s. At the same time, compared with the micro-groove structure, the delayed icing ability of the micro-column structure is more excellent. The reason may be that compared with the unidirectional gas film supporting the droplet on the micro-groove structure, the gas film supporting the droplet on the micro-column structure surface is bidirectional, which makes the superhydrophobic ability of the micro-column surface more stable and avoids the phenomenon that the droplet falls into the groove with time due to the unstable gas film, providing favorable conditions for delaying icing.

[0074] Example 3

[0075] This example involves cutting indexes such as cutting force and surface roughness obtained by milling micro-groove structures with or without cold plasma jet assistance, providing theoretical support for the high-quality and efficient processing of the anti-icing structure on the surface of 30CrMnSiNi2A material. Compare the processing indexes of micro-groove structures under different working conditions: Under the same processing parameters as in Example 1, compare the processing indexes such as cutting force and surface quality of the micro-groove structures obtained with or without cold plasma jet-assisted cutting. At the same time, in order to avoid the influence of air flow impact on the micro-groove processing results, a nitrogen jet-assisted milling test was carried out.

[0076] As Figure 2 and Figure 3As shown, there is no obvious difference in the cutting force and surface roughness of the micro-groove structures obtained under dry (without cold plasma jet assistance) and nitrogen jet assistance. However, the cold plasma jet rich in active particles can reduce the cutting force and cutting deformation during milling through the Rehbinder effect and effectively improve the surface quality of the micro-groove structure. At the same time, the tool life is extended by 1.5 times, which is of great significance for realizing high-quality and efficient machining of the anti-icing structure on the surface of 30CrMnSiNi2A material.

[0077] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can make several deformations or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A processing method for a surface anti-icing microstructure, characterized in that a micro-milling device for processing the surface anti-icing microstructure is adopted; the surface anti-icing microstructure is a micro-groove structure and / or a micro-column structure; for the micro-groove structure, the ridge width d = 200 μm, the groove width w = 500 μm, and the groove depth h = 600 μm; for the micro-column structure, the column width d = 500 μm, the groove width w = 500 μm, and the groove depth h = 600 μm; the micro-milling device is composed of an atmospheric pressure cold plasma jet generating device and a processing machine tool; the atmospheric pressure cold plasma jet generating device includes a working gas source (1), a pressure reducing valve (2), a flow meter (3), a discharge nozzle (4), and a working power supply (9); the processing machine tool includes a cutting tool (6) and a working machine tool (8); The method includes the following steps: Cut, grind, polish, and clean the workpiece (7) to determine the area to be processed on the workpiece (7); clamp the workpiece (7) on the working machine tool (8), align the discharge nozzle (4) and the cutting tool (6) with the area to be processed on the workpiece (7), perform processing, machine a micro-groove structure and / or a micro-column structure in the area to be processed on the workpiece (7), ultrasonically clean, dry, immerse the workpiece (7) in a low surface energy substance, and dry it to obtain the surface anti-icing microstructure.

2. The processing method for the surface anti-icing microstructure according to claim 1, characterized in that the working gas source (1) adjusts the gas pressure and flow rate through the pressure reducing valve (2) and the flow meter (3), transports the gas to the discharge nozzle (4), the output end of the working power supply (9) is connected to the corresponding electrode of the discharge nozzle (4), when the gas is introduced into the discharge nozzle (4), a discharge voltage and frequency are applied to generate a stable light purple cold plasma jet (5) to achieve real-time modification of the position to be processed.

3. The processing method for the surface anti-icing microstructure according to claim 1, characterized in that the working machine tool (8) is used to clamp the workpiece (7) to be processed; the cutting tool (6) is aligned with the area to be processed on the workpiece (7) and cooperates with the cold plasma jet (5) to process the workpiece (7).

4. The processing method for the surface anti-icing microstructure according to claim 1, characterized in that the parameters of the working machine tool (8) are as follows: the spindle speed n of the machine tool = 20000 rpm to 50000 rpm; the feed rate Vf = 200 μm / s to 1100 μm / s; the cutting depth ap = 5 μm to 20 μm.

5. The processing method for the surface anti-icing microstructure according to claim 1, characterized in that the parameters of the cold plasma jet (5) are as follows: the gas pressure P = 0.4 MPa to 0.6 MPa; the gas flow rate Q = 8 L / min to 12 L / min; the discharge voltage U = 2 kV to 3 kV; the frequency f = 50 kHz to 60 kHz.

6. The processing method for the surface anti-icing microstructure according to claim 1, characterized in that the angle α between the discharge nozzle (4) and the horizontal plane = 30° to 60°, and it is parallel to the feed direction of the cutting tool (6).

7. The processing method of the surface anti-icing microstructure according to claim 1, wherein the low surface energy substance is selected from at least one of an ethanol solution of fluorosilane, an ethanol solution of octadecyltrichlorosilane, or an ethanol solution of polydimethylsiloxane.

8. The processing method of the surface anti-icing microstructure according to claim 1, wherein the concentration of the ethanol solution of fluorosilane is 0.5 to 2 wt%; the concentration of the ethanol solution of octadecyltrichlorosilane is 1 to 3 wt%; the concentration of the ethanol solution of polydimethylsiloxane is 1 to 10 wt%.

9. The processing method of the surface anti-icing microstructure according to claim 1, wherein the working gas source (1) of the atmospheric pressure cold plasma jet generating device is selected from at least one of nitrogen, argon, helium, water vapor, oxygen, and filtered and dried air.

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