Complex micro internal flow channel fluid polishing method based on weak oxidation and micro friction composite effect

Abstract

The invention provides a complex micro-fine inner flow channel fluid polishing method based on a weak oxidation and micro-friction composite effect, which comprises the following steps: conveying a polishing solution containing micro-nano bubbles into an inner flow channel of a to-be-polished workpiece according to preset parameters, and swinging and / or rotating the to-be-polished workpiece in a reciprocating manner according to the preset parameters, polishing of an inner runner of the workpiece is achieved; wherein a uniform amorphous oxide layer is formed on the surface of the inner flow channel through the comprehensive action of an oxidizing agent, a corrosion inhibitor and a surfactant which are arranged in the polishing solution, and then the amorphous oxide layer is stripped through the comprehensive action force generated by fluid movement and micro-nano bubble explosion; and polishing of the inner runner of the workpiece is realized by circularly performing the processes of forming the amorphous oxide layer and stripping the amorphous oxide layer. According to the method disclosed by the invention, weak corrosion and micro-friction stripping are circularly carried out by combining the combined action of the chemical corrosion force of the polishing solution and the mechanical friction force of the fluid and the micro-nano bubbles, so that uniform and effective processing of the inner runner is realized.

Description

Technical Field

[0001] The invention relates to the technical field of fluid polishing, and in particular to a complex micro-internal flow channel fluid polishing method based on the composite effect of weak oxidation and micro-friction. Background Art

[0002] The inner flow channel is the main structure responsible for gas / liquid transport, heat control and exchange, and is widely used in aerospace, shipbuilding, automobile, microelectronics, molds and other fields. With the increasing requirements of modern high-end equipment for miniaturization and lightweight devices, the inner flow channel is developing towards a smaller caliber and more complex structure. The application of micro inner flow channels including S-shaped bends, U-shaped bends, O-shaped bends, spiral bends and bifurcations is increasing. Common molding methods for inner flow channels include organic machining, electric spark, additive manufacturing, etc., but no matter what molding method is used, it cannot be guaranteed that there are no defects such as machining lines, cracks, ablation, powder sticking, convex and concave points inside. These defects make the inside of the flow channel rough and the flow resistance huge, which significantly reduces the flow channel transport efficiency, and the risk of crack development is high, affecting the safety and life of parts. At the same time, if adhesion particles and burrs fall off during use, it may cause blockage of the flow channel, and even impurities may enter other connecting working systems and cause damage to the equipment. Therefore, proper surface treatment is imperative.

[0003] Contact friction removal technology is a processing method that relies on the mechanical friction of grinding tools (such as grinding heads, knives, abrasives, etc.) to remove bumps on the product surface. It is the most traditional and commonly used surface polishing technology. At present, contact friction removal technology has also been used in the field of internal flow channel polishing. However, since contact friction removal technology is limited by the size and profiling ability of grinding tools, this type of method is suitable for large-caliber (such as Φ>10mm) straight internal flow channels or simple internal flow channels with large curvature, and cannot meet the surface treatment requirements of small-caliber (such as Φ<5mm), large variable diameters, or complex and fine internal flow channels containing S-shaped bends, U-shaped bends, O-shaped bends, spiral bends and bifurcations.

[0004] Another common internal flow channel polishing technology is to use the flexibility of high-viscosity non-Newtonian fluids and the cutting force of hard abrasives to work, that is, abrasive flow polishing technology, which is also a type of improved contact friction removal technology and the most commonly used internal flow channel processing technology. However, since it is a strong hard extrusion technology, it is easy to cause over-polishing of the port, and it is not suitable for thin-walled parts and large-diameter and small-curvature internal flow channel processing. At the same time, there is also the problem of difficulty in cleaning abrasive residues.

[0005] With the development of technology, improved abrasive flow machining technologies have emerged one after another. For example, magnetic field assistance is used to achieve uniform machining of complex curved surfaces, and elastic fluid containing polishing abrasives is used between elastic profiling bodies and profiling magnetic tiles inside and outside the titanium alloy cavity wall to achieve machining of titanium alloy inner cavities. However, due to the difficulty of molds, abrasives and high-viscosity fluids entering micro-channels, both cannot achieve the machining of complex cavities or internal flow channels with small diameters, large diameters or variable shapes and structures, and there is a problem that abrasive residues are difficult to clean up, and post-processing is difficult. In addition, some of them also require fixed-value special high-precision profiling molds, which has high processing costs.

[0006] Low-viscosity fluids have good conformability and are applicable to a wide range of structures. They are an effective alternative solution to the problem of polishing complex and fine internal channels. However, pure chemical polishing has the disadvantages of strong corrosion and high operational risk. It also has the problems of difficult processing rate control and limited leveling ability. If it is combined with electrochemical polishing, plasma and other polishing technologies, it needs to rely on electric field drive. However, due to the electric field shielding effect inside the metal, it is only suitable for complex external surface processing and is ineffective for internal channel processing.

[0007] Therefore, the polishing technology of fine and complex internal flow channels has become one of the key technical bottlenecks restricting its large-scale application. It is urgent to develop new technical means to solve this industry problem.

[0008] Prior art literature:

[0009] Chinese patent: CN206998477

[0010] Chinese patent: CN117506692

[0011] Chinese patent: CN118181124

[0012] Chinese patent: CN109079590

[0013] Chinese patent: CN117300749. Summary of the invention

[0014] The purpose of the present invention is to address the deficiencies of the prior art and to provide a method for fluid polishing of complex and fine inner flow channels based on the combined effect of weak oxidation and micro-friction. An amorphous oxide layer is formed on the surface of the inner flow channel through weak oxidation, and then the amorphous oxide layer is peeled off through the combined force of the micro-jets of fluid movement combined with the collapse shock waves of micro-nano bubbles. Through the cyclic alternation of forming and peeling off the amorphous oxide layer, effective leveling and polishing of the inner flow channel is achieved.

[0015] According to the purpose of the present invention, a complex micro-channel fluid polishing method based on the combined effect of weak oxidation and micro-friction is provided, comprising:

[0016] A polishing solution containing micro-nano bubbles is delivered into the inner flow channel of the workpiece to be polished according to preset parameters, and the workpiece to be polished is reciprocated and / or rotated according to preset parameters to achieve polishing of the inner flow channel of the workpiece;

[0017] Among them, a uniform amorphous oxide layer is formed on the surface of the inner flow channel through the combined action of the oxidant, corrosion inhibitor and surfactant set in the polishing solution, and then the amorphous oxide layer is peeled off through the combined action force generated by fluid movement and micro-nano bubble explosion; the polishing of the inner flow channel of the workpiece is achieved by cyclically forming and peeling off the amorphous oxide layer.

[0018] As an optional embodiment, the polishing solution includes an oxidant, a corrosion inhibitor, a surfactant, an auxiliary agent and pure water.

[0019] As an optional embodiment, the oxidant accounts for 1wt% to 10wt% of the polishing solution, including one or more of copper sulfate, sodium sulfate, sodium persulfate, potassium persulfate, sodium oxide, sodium carbonate, sodium bicarbonate, sodium citrate, sodium chloride, ammonium chloride, sodium fluorosilicate, cerium nitrate, and hydrogen peroxide.

[0020] As an optional embodiment, the corrosion inhibitor accounts for 0.1wt% to 1wt% of the polishing solution, including one or more of sodium silicate, sodium metaphosphate, sodium tripolyphosphate, aminoacetic acid, succinic acid, benzotriamino azole, polyethylene glycol, and sodium carboxymethyl cellulose.

[0021] As an optional embodiment, the surfactant accounts for 0.01wt% to 1wt% of the polishing solution, including one or more of sodium dodecylbenzene sulfonate, monolauryl phosphate, lauryl ether phosphate, coconut acid diethanolamide, disodium lauryl iminodiacetic acid, diethylhexanol, tributyl phosphate, and polyoxyethylene polyoxypropylene copolymer.

[0022] As an optional implementation, the polishing solution has a mass percentage of 1% to 10%, a viscosity of 1 to 30 cP, and a pH of 5 to 9.

[0023] As an optional implementation, the volume fraction of the micro-nano bubbles in the polishing solution is 3% to 15%, and the size of the micro-nano bubbles is 0.01 μm to 100 μm.

[0024] As an optional embodiment, the step of delivering a polishing solution containing micro-nano bubbles into an inner flow channel of a workpiece to be polished according to preset parameters comprises:

[0025] The pressure of the output polishing solution is 0.1Mpa~1.0Mpa, and the flow rate is 0.02m 3 / h~1m 3 / h, the working temperature of the polishing solution is 30±20℃.

[0026] As an optional embodiment, the step of causing the workpiece to be polished to reciprocate and / or rotate according to preset parameters includes:

[0027] The reciprocating swing speed is 0.1m / s~1.2m / s, the swing distance is 10mm~100mm, and the rotation speed is 0.1m / s~1.0m / s.

[0028] As an optional embodiment, in the process of conveying the polishing solution containing micro-nano bubbles into the inner flow channel of the workpiece to be polished, the polishing solution is circulated and the micro-nano bubbles are injected before being conveyed to the inner flow channel of the workpiece to be polished.

[0029] It can be seen from the above technical solutions of the present invention that the complex micro-inner flow channel fluid polishing method based on the composite effect of weak oxidation and micro-friction proposed by the present invention adopts a low-viscosity fluid combined with micro-nano bubbles, and through the combined effect of the chemical corrosion force of the oxidant and the mechanical friction force of the fluid and micro-nano bubbles, the weak corrosion and micro-friction peeling cycle is carried out, thereby achieving uniform and effective processing of the complex micro-inner flow channel;

[0030] During the working process of the polishing method, the weak chemical force of the oxidant is used to form an extremely thin amorphous oxide layer on the surface of the product. This metastable porous soft film has poor wear resistance and corrosion resistance and is called a micro-corrosion layer. At the same time, the development of the micro-corrosion layer is controlled by a corrosion inhibitor, and the processing uniformity is guaranteed by a surfactant to form a uniform amorphous oxide layer. Then, the micro-corrosion layer is peeled off by the combined force generated by fluid movement and micro-nano bubble explosion to expose the fresh substrate surface, so that the micro-oxidation-corrosion inhibition-peeling polishing process can be continuously circulated. Since the tip solution has a strong wetting ability and a large fluid friction force, the tip oxidation-corrosion inhibition-peeling cycle is faster and the removal rate is higher. In this way, the tip can be flattened by continuous circulation, that is, effective flattening and polishing of the workpiece surface can be achieved;

[0031] Therefore, the method of the present invention can achieve uniform and effective processing of complex and fine internal flow channels of various structures and calibers, and is also suitable for thin-wall flow channel processing. Its applicable flow channel range is wider than the existing internal flow channel polishing technology, and its processing uniformity is good, the surface is clean and there is no residue, and there is no need to customize special molds. The operation is simple, the processing process is easy to control, and the processing cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of an exemplary complex micro-inner flow channel fluid polishing device based on the combined effect of weak oxidation and micro-friction of the present invention.

[0033] Figure 2It is a process flow chart of an exemplary method of fluid polishing of complex micro-inner flow channels based on the combined effect of weak oxidation and micro-friction according to the present invention. DETAILED DESCRIPTION

[0034] In order to better understand the technical content of the present invention, specific embodiments are given and described as follows in conjunction with the accompanying drawings.

[0035] Various aspects of the present invention are described in this disclosure with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the present disclosure are not necessarily intended to include all aspects of the present invention. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of many ways.

[0036] Combination Figure 1-2 The complex micro-inner flow channel fluid polishing method based on the combined effect of weak oxidation and micro-friction is a processing method that relies on the synergistic effect of the weak oxidation force of low-concentration, low-viscosity fluid and the mechanical friction force of the fluid and micro-nano bubbles to achieve cyclic peeling of the workpiece surface. It combines the weak corrosion force and micro-friction force of the weak oxidizing fluid to level the inner flow channel surface, and achieves uniform and effective polishing of complex micro-inner flow channels of various structures, calibers, and wall thicknesses.

[0037] Fluid polishing device for complex micro-channels based on the combined effect of weak oxidation and micro-friction

[0038] like Figure 1 As shown, the exemplary complex micro-inner channel fluid polishing device based on the combined effect of weak oxidation and micro-friction of the present invention includes: a working tank 10, a circulation system 20, a micro-nano bubble generating device 30, a filtering system 40, a workpiece clamping system 50 and a control system 60.

[0039] The working tank 10 has an inner cavity, which defines a working area for polishing the workpiece; a polishing solution 70 is arranged at the lower part of the inner cavity of the working tank, and the workpiece clamping system 50 is arranged at the upper part of the inner cavity of the working tank, so that the workpiece clamping system 50 is located above the polishing solution 70 and is not submerged by the polishing solution 70.

[0040] A drain port connected to the inner cavity is provided at the bottom of the working tank 10. One end of the circulation system 20 is connected to the drain port and is configured to be a structure for transporting the polishing solution 70. The other end of the circulation system is connected to the inlet of the inner flow channel to be processed of the workpiece 90 fixedly clamped by the workpiece clamping system 50 through a guide pipe 80.

[0041] A circulation drive device 21 is configured in the circulation system 20, a filtering system 40 is provided between the circulation drive device 21 and the drain port, and a micro-nano bubble generating device 30 is provided between the circulation drive device 21 and the guide tube 80. The micro-nano bubble generating device 30 is used to generate micro-nano bubbles and inject them into the polishing solution 70 during the process of transporting the polishing solution 70 in the circulation system. The micro-nano bubbles are transported to the inner flow channel to be processed together with the polishing solution 70 to participate in the polishing process, and flow out from the inner flow channel outlet of the workpiece 90 together with the polishing solution 70, enter the lower part of the inner cavity of the working tank and continue to participate in the circulation of the polishing solution.

[0042] Preferably, a pipeline 23 is provided in the circulation system as a transport channel for the polishing solution, and the drain port, the filtration system 40, the circulation drive device 21, the micro-nano bubble generating device 30, and the guide tube 80 are connected through the pipeline 23.

[0043] In this way, the circulation drive device 21 draws the polishing solution 70 from the drain port at the bottom of the working tank 10, starts to transport it through the pipeline 23, reduces the concentration of impurities and / or particles in the polishing solution transported to the surface of the workpiece through the filtration system 40, and then injects micro-nano bubbles through the micro-nano bubble generating device 3, and then continues to be transported to the guide pipe 80 through the pipeline 23 until it is transported to the entrance of the inner flow channel of the workpiece 90 to participate in processing, and then returns to the working tank 10 from the outlet of the inner flow channel, thereby realizing the recycling of the polishing solution 70.

[0044] An adjusting device 22, such as a regulating valve, is provided at one end of the circulation system 20 near the guide tube 80 to control the pressure of the polishing solution, ensure the stability of the processing, and avoid deformation of the workpiece or damage to the pipeline due to excessive pressure.

[0045] Preferably, the flow rate, pressure, etc. of the extracted polishing solution 70 can be adjusted by the circulation driving device 21 , and the size, proportion, etc. of the generated micro-nano bubbles can be controlled by the micro-nano bubble generating device 30 .

[0046] The workpiece clamping system 50 enables the workpiece 90 to perform multiple posture movements such as translation, swing, and rotation through the configured motion mechanism 51.

[0047] The control system 60 is arranged outside the working tank 10, and can realize the power system control, circulation drive device control, micro-nano bubble generating device control, motion mechanism control and temperature control during the processing, so as to realize the comprehensive adjustment of the polishing effect.

[0048] A protective cover 11 is provided at the top of the working tank 10 to prevent liquid or water vapor from splashing out, thereby ensuring a safe and clean environment.

[0049] In a preferred example, the guide tube 80 is a bendable corrosion-resistant hose, and the guide port fits tightly with the inlet of the flow channel in the workpiece to ensure that there is no leakage of liquid.

[0050] In some other examples, the flow guide tube 80 may have one or more stages of diameter changes until it changes to a suitable flow guide port diameter to better connect to the inner flow channel inlet.

[0051] In a more preferred example, the diameter of the guide port needs to be larger than the maximum diameter of the flow channel in the workpiece (if it is a multi-branch flow channel, the sum of the diameters of the branch flow channels is taken) to fill the flow channel with fluid and maintain a certain pressure to obtain sufficient fluid friction to ensure processing uniformity.

[0052] In a more specific example, the diameter R of the guide port is determined by the maximum diameter r of the flow channel in the workpiece, and the effect is best when R=(1.2~2.6)r.

[0053] In other optional examples, the polishing device is further provided with a temperature control system for controlling the temperature of the polishing solution to perform processing within a desired range.

[0054] Fluid polishing method for complex micro-channels based on the combined effect of weak oxidation and micro-friction

[0055] Combination Figure 2 As shown, using the aforementioned polishing device, the exemplary complex micro-inner flow channel fluid polishing method based on the weak oxidation and micro-friction composite effect of the present invention includes:

[0056] A polishing solution containing micro-nano bubbles is delivered into the inner flow channel of the workpiece to be polished according to preset parameters, and the workpiece to be polished is reciprocated and / or rotated according to preset parameters to achieve polishing of the inner flow channel of the workpiece;

[0057] Among them, a uniform amorphous oxide layer is formed on the surface of the inner flow channel through the combined action of the oxidant, corrosion inhibitor and surfactant set in the polishing solution, and then the amorphous oxide layer is peeled off through the combined action force generated by fluid movement and micro-nano bubble explosion; the polishing of the inner flow channel of the workpiece is achieved by cyclically forming and peeling off the amorphous oxide layer.

[0058] As an optional example, the mass percentage of the polishing solution is 1% to 10%, the viscosity is 1 to 30 cP, and the pH is 5 to 9. The polishing solution of this concentration and viscosity belongs to the category of low-concentration, low-viscosity fluid polishing, which can ensure sufficient oxidation and filling capabilities for complex and fine internal flow channels, and ensure product processing uniformity. The pH value is 5 to 9, which is less corrosive and relatively safe for the environment and human body.

[0059] As an optional example, the total amount of polishing solution is 10 to 30 times greater than the total volume of the flow channel in the workpiece to ensure that sufficient solution participates in the circulation and the temperature fluctuation range of the solution can be effectively controlled.

[0060] As an optional example, the components of the polishing solution include an oxidant, a corrosion inhibitor, a surfactant, an auxiliary agent, and pure water.

[0061] As an optional example, the oxidant accounts for 1wt% to 10wt% of the polishing solution, including one or more of copper sulfate, sodium sulfate, sodium persulfate, potassium persulfate, sodium oxide, sodium carbonate, sodium bicarbonate, sodium citrate, sodium chloride, ammonium chloride, sodium fluorosilicate, cerium nitrate, and hydrogen peroxide.

[0062] The oxidant set in the polishing solution used in the present invention is a weak oxidant. First, through its weak oxidation effect, an extremely thin amorphous oxide layer is formed on the surface of the workpiece. This is a metastable porous soft film with poor wear resistance and corrosion resistance. It is called a micro-corrosion layer and is the primary condition for the work of the present invention.

[0063] Due to the instability of the micro-corrosion layer, if mechanical friction is introduced into the flow channel at this time, the metastable micro-corrosion layer will be continuously divided, peeled off and removed under the action of friction. If the oxidizing environment continues to be maintained, the micro-corrosion layer will extend into the substrate, and gradually thicken, harden and become continuous, and even grow into a stable crystalline oxide layer covering the entire surface. The wear and corrosion resistance of this oxide layer is significantly enhanced, and the weak friction brought by the fluid is not enough to peel it off, so the polishing process stops.

[0064] As an optional example, the corrosion inhibitor accounts for 0.1 wt% to 1 wt% of the polishing solution, including one or more of sodium silicate, sodium metaphosphate, sodium tripolyphosphate, aminoacetic acid, succinic acid, benzotriamino azole, polyethylene glycol, and sodium carboxymethyl cellulose.

[0065] The function of the corrosion inhibitor set in the polishing solution used in the present invention is to inhibit the development of the micro-corrosion layer into a crystalline thick oxide layer, so that the surface of the workpiece can maintain a loose, soft, amorphous state, thereby reducing the difficulty of mechanical friction removal, and avoiding further corrosion of the substrate by the oxidant, thereby avoiding over-corrosion of the workpiece due to long-term immersion in the polishing solution.

[0066] As an optional example, the surfactant accounts for 0.01wt% to 1wt% of the polishing solution, including one or more of sodium dodecylbenzene sulfonate, monolauryl phosphate, lauryl ether phosphate, coconut acid diethanolamide, disodium lauryl iminodiacetic acid, diethylhexanol, tributyl phosphate, and polyoxyethylene polyoxypropylene copolymer.

[0067] The surfactant provided in the polishing solution used in the present invention can significantly reduce the surface tension between the polishing solution and the workpiece, and improve the accessibility of the solution to local complex structures. Its function is to improve oxidation uniformity, that is, it helps to improve processing uniformity.

[0068] The surfactant of the present invention is preferably a small bubble type to avoid generating too many large bubbles during the solution circulation process and affecting the polishing effect. It is particularly preferably at least one of sodium dodecylbenzene sulfonate, monolauryl phosphate, lauryl ether phosphate, coconut oil diethanolamide, and disodium lauryl iminodiacetate, and at least one of diethylhexanol, tributyl phosphate, and polyoxyethylene polyoxypropylene copolymer.

[0069] As an optional example, the additive accounts for 0.01wt% to 0.1wt% of the polishing solution, including at least one of ethylenediaminetetraacetic acid, citric acid, malic acid, oxalic acid, sodium hydroxide, and potassium hydroxide. The role of the additive is to maintain the stability of the solution system and adjust the pH.

[0070] It is understandable that when there is more than one type of oxidant, the components can be combined in any ratio, and the same applies to corrosion inhibitors, surfactants and additives.

[0071] The polishing solution provided by the present invention is a mutually influencing equilibrium system. Different components cooperate with each other and match reasonable processing technology to achieve a good surface polishing effect. If the oxidizing property is too weak, it is not enough to form an amorphous film, and the processing process cannot be carried out; if the oxidizing property is too strong and the corrosion inhibition ability is insufficient, it is impossible to form an effective protective and maintaining amorphous film on the surface of the workpiece, which is easy to cause local over-corrosion or even overall over-corrosion of the product.

[0072] As an optional example, the content and size of micro-nano bubbles in the polishing solution can be controlled by adjusting the micro-nano bubble generating device, and the fluid force can be adjusted by controlling the energy generated when the micro-nano bubbles collapse, thereby regulating the processing effect of complex micro-channels.

[0073] In one preferred example, the volume fraction of the micro-nano bubbles in the polishing solution is 3% to 15%, and the size of the micro-nano bubbles is 0.01 μm to 100 μm.

[0074] Micro-nano bubbles refer to highly compressed bubbles with sizes in the micron and nanometer range. They have a series of characteristics different from conventional bubbles, such as large specific surface area, slow rising speed in water, high gas solubility rate, high mass transfer efficiency, and high negative charge. When they collapse, they can produce shock waves and microjets with a pressure greater than 50MPa and a speed greater than 400KM / H directed to the surface of the workpiece, and release a large number of hydroxyl free radicals with ultra-high redox potential. They have super strong oxidizing effects and are widely used in wastewater and waste gas treatment, cleaning, aquatic products, and beauty. In recent years, they have also received increasing attention in the polishing field.

[0075] The present invention injects micro-nano bubbles into the polishing solution. In addition to the shear friction generated by the fluid movement on the workpiece surface, the high-pressure and high-speed shock waves and microjets directed to the workpiece surface generated when the micro-nano bubbles collapse near the workpiece surface also have an obvious leveling effect on the workpiece surface. At the same time, the collapsed shock waves and microjets can also greatly improve the filling capacity and movement capacity of the fluid in the flow channel, which is beneficial to the timely stripping and transportation of the micro-corrosion layer on the workpiece surface, that is, it is beneficial to the continuous polishing process, and can effectively improve the processing efficiency and processing uniformity. At the same time, oxygen is a safe and effective oxidant. The micro-nano bubbles contain a large amount of compressed oxygen. The large amount of strong oxidizing free radicals released when the micro-nano bubbles collapse can greatly improve the oxidizing activity of the solution. This is also one of the reasons why the present invention can use a low-concentration polishing solution to obtain good oxidation and polishing effects.

[0076] As an optional example, a polishing solution containing micro-nano bubbles is delivered to the inner flow channel of the workpiece to be polished according to preset parameters, including: the pressure of the output polishing solution is 0.1Mpa to 1.0Mpa, the flow rate is 0.02m 3 / h~1m 3 / h, the working temperature of the polishing solution is 30±20℃.

[0077] The low-pressure, slow-speed processing method is conducive to keeping the flow channel full and preventing the fluid pressure from being too high, thus avoiding uneven processing and even damage to the workpiece caused by the large force difference between the front and rear ends of the flow channel bend in high-pressure and high-speed fluid polishing technology. The low-pressure and slow-speed processing method exerts a more uniform and gentle force on the entire flow channel, which also makes it suitable for polishing the flow channel in thin-walled structures that are easily deformed.

[0078] As an optional example, the workpiece to be polished is reciprocated and / or rotated according to preset parameters, including: a reciprocating swing speed of 0.1m / s to 1.2m / s, a swing distance of 10mm to 100mm, and a rotation speed of 0.1m / s to 1.0m / s.

[0079] Due to the huge difference in force between the front and rear ends of the bend in the flow channel, the front end of the flow channel facing the direction of the fluid is usually overshot or even perforated due to the large positive impact force, but the rear end of the opposite direction is difficult to process due to the severe attenuation of fluid pressure.

[0080] Therefore, the workpiece can be made to perform multi-posture movements such as translation, swinging, and rotation as needed. Such a setting can enhance the spiral or turbulent motion ability of the fluid in the flow channel, improve the fluid filling ability, extend the fluid movement path, increase the friction force, and significantly reduce the force difference between the front and rear ends of the curved flow channel, avoid the difference in processing effects at the front and rear ends of the curved flow channel, thereby improving the overall processing uniformity and efficiency of the inner flow channel, which is particularly important for multi-bend flow channels and large variable diameter flow channels.

[0081] In addition, the multi-posture movement of the workpiece will also increase the residence time of micro-nano bubbles in the workpiece area, which helps to improve the effective utilization of micro-nano bubbles.

[0082] As an optional embodiment, in the process of transporting the polishing solution containing micro-nano bubbles into the inner flow channel of the workpiece to be polished, the polishing solution is circulated and the micro-nano bubbles are injected before being transported to the inner flow channel of the workpiece to be polished; the recycling of the polishing solution not only ensures the solution utilization rate but also ensures the stability of the solution temperature, which is conducive to maintaining a steady processing rate.

[0083] In one typical example of the present invention, in combination with the aforementioned polishing device, a complex micro-inner flow channel fluid polishing method based on the combined effect of weak oxidation and micro-friction includes:

[0084] Step 1: Prepare a proper amount of polishing solution 70 in the working tank 10. The polishing solution 70 can be a low-concentration water-soluble solution with a mass percentage of 1% to 10%, a viscosity of 1 to 30 cP, and a pH of 5 to 9.

[0085] The components of the polishing solution include an oxidant, a corrosion inhibitor, a surfactant, an additive and pure water, and the oxidant includes one or more of copper sulfate, sodium sulfate, sodium persulfate, potassium persulfate, sodium oxide, sodium carbonate, sodium bicarbonate, sodium citrate, sodium chloride, ammonium chloride, sodium fluorosilicate, cerium nitrate and hydrogen peroxide, accounting for 1wt% to 10wt% of the polishing solution;

[0086] The corrosion inhibitor includes one or more of sodium silicate, sodium metaphosphate, sodium tripolyphosphate, aminoacetic acid, succinic acid, benzotriaminoazole, polyethylene glycol, and sodium carboxymethyl cellulose, accounting for 0.1wt% to 1wt% of the polishing solution;

[0087] The surfactant includes one or more of sodium dodecylbenzene sulfonate, monolauryl phosphate, lauryl alcohol ether phosphate, coconut acid diethanolamide, disodium lauryl iminodiacetate, diethylhexanol, tributyl phosphate, and polyoxyethylene polyoxypropylene copolymer, accounting for 0.01wt% to 1wt% of the polishing solution;

[0088] The auxiliary agent includes one or more of ethylenediaminetetraacetic acid, citric acid, malic acid, oxalic acid, sodium hydroxide and potassium hydroxide, accounting for 0.01wt% to 0.1wt% of the polishing solution.

[0089] Step 2: Fix the workpiece 90 in the workpiece clamping device 50, connect the drain port, the filtration system 40, the circulation drive device 21, the micro-nano bubble generating device 30, and the guide tube 80 through the pipeline 23, and connect the guide tube 80 to the inner flow channel of the workpiece 90 to be processed. The guide port is tightly fitted with the entrance of the inner flow channel of the workpiece to ensure that there is no leakage of liquid.

[0090] Step 3: Set the pressure of the polishing solution output by the circulation drive device 21 to 0.1Mpa-1.0Mpa and the flow rate to 0.02m 3 / h-1m 3 / h, control the working temperature of the polishing solution to 30±20℃; set the working conditions of the micro-nano bubble generating device 30, the micro-nano bubble content is 3%~15%, and the micro-nano bubble size is 0.01μm~100μm; set the workpiece movement conditions, such as lifting speed, translation speed, rotation speed, etc.; start the power supply through the control system 60, start the circulation drive device 21, extract the filtered polishing solution from the working tank 10, transport it to the micro-nano bubble generating device 30 through the pipeline system to inject micro-nano bubbles, and then transport it to the inner flow channel to be processed of the workpiece 90 through the guide pipe, and start processing until polishing is completed.

[0091] Step 4: Take out the workpiece, clean it with pure water for 10 minutes, replace it with new water and clean the inner flow channel for 10 minutes or more until the water is clear and free of impurities, pH = 7, then blow dry the inner flow channel with an air gun and dry the workpiece.

[0092] The polishing method of the present invention has the following advantages:

[0093] 1. Wide application scope. The polishing solution selected by the present invention is a low-concentration, low-viscosity fluid. Thanks to its high conformability, the polishing solution of the present invention can easily enter long and deep holes with a diameter less than 5mm or even less than 1mm, and can also easily shuttle in complex internal flow channels containing S-shaped bends, U-shaped bends, O-shaped bends, spiral bends and bifurcations, and has a very strong filling capacity for complex micro-flow channels; at the same time, in addition to the promotion of the fluid by the circulation system, micro-nano bubbles and motion mechanisms are also provided to assist and enhance the fluid filling capacity and motion peeling capacity, which helps to improve the uniformity and efficiency of workpiece processing; therefore, the present invention belongs to a high-flexibility processing technology, which can realize uniform and effective processing of complex micro-inner flow channels of various structures and calibers, and is also suitable for thin-walled flow channel processing, and its applicable flow channel range is wider than the existing internal flow channel polishing technology; at the same time, with a suitable polishing solution system, the present invention can be applied to the processing of internal flow channels of various materials such as titanium alloys, aluminum alloys, copper alloys, stainless steel, and mold steel.

[0094] 2. Good processing uniformity. The present invention is a low-pressure, slow, high-flexibility processing technology. The impact force on the flow channel is weak and uniform, which avoids the huge force difference before and after the flow channel bends in high-pressure and fast processing methods such as abrasive flow, and prevents the problem of over-throwing at the front end and difficult processing at the back end, which better guarantees the processing uniformity.

[0095] 3. Clean and residue-free. The polishing medium of the present invention is a water-soluble, near-neutral, low-concentration solution, and does not use hard abrasive particles, so it can be cleaned by washing with water after processing. The processed product is clean and residue-free, and there is no problem of waste liquid and abrasive residue. During the use of the workpiece, there is no risk of abrasive residue blocking the flow channel or particles entering other working systems to cause equipment damage. The near-neutral weakly corrosive solution system is relatively safe for the environment and human body, does not involve solid waste, and the post-processing is relatively simple.

[0096] 4. Simple operation and low processing cost. At the same time, low-viscosity fluids have good adaptability, and do not require special cutting tools (grinding heads, blocking balls, yarns, abrasive particles, etc.), nor do they require customized special molds. The operation is simple, the processing process is easy to control, and the processing cost is low.

[0097] For better understanding, the present invention is further described below in conjunction with several specific examples, but the preparation process is not limited thereto, and the content of the present invention is not limited thereto.

[0098] Unless otherwise specified, the materials in the examples were prepared according to existing methods or directly purchased from the market.

[0099] Example 1

[0100] Implementation conditions: The workpiece is an additively manufactured S-type TC4 inner flow channel with an inner diameter of 5 mm and an original roughness of about 7.8 μm.

[0101] Step 1: Prepare 2L of polishing solution in the working tank, add oxidant, corrosion inhibitor, surfactant and a small amount of additives in proportion, and mix evenly. The mass fraction of the polishing solution is 8%, the viscosity is 8cP, and the pH is 6.

[0102] Among them, the oxidants are copper sulfate, sodium persulfate, sodium citrate, ammonium chloride, sodium fluorosilicate and cerium nitrate (mass ratio of 1:4:3:4:1:2), accounting for 7.5% of the mass of the polishing solution; the corrosion inhibitors are aminoacetic acid, benzotriaminoazole and polyethylene glycol (mass ratio of 2:1:1), accounting for 0.45% of the mass of the polishing solution; the surfactants are sodium dodecylbenzene sulfonate and polyoxyethylene polyoxypropylene copolymer (mass ratio of 3:1), accounting for 0.04% of the mass of the polishing solution; the additives are ethylenediaminetetraacetic acid and malic acid (mass ratio of 1:2), accounting for 0.01% of the mass of the polishing solution.

[0103] Step 2: Fix the workpiece in the workpiece clamping device, connect the drain port, filtration system, circulation drive device, micro-nano bubble generating device, and guide tube through pipelines, and connect the guide tube to the inner flow channel of the workpiece to be processed. The guide end of the guide tube has a diameter of 8mm and fits tightly with the inlet of the inner flow channel of the workpiece to ensure that there is no leakage of liquid.

[0104] Step 3: Set the pressure of the polishing solution output by the circulation drive device to 0.4Mpa and the flow rate to 0.3m 3 / h, set the working temperature of the polishing solution to 30±20℃; set the micro-nano bubble generating device to make the micro-nano bubble content 8% and the micro-nano bubble size 50μm; set the reciprocating swing speed of the workpiece to 0.6m / s and the swing distance to 50mm.

[0105] The power supply is started through the control system, the circulation drive device is started, the filtered polishing solution is extracted from the working tank, transported to the micro-nano bubble generating device through the pipeline, injected with micro-nano bubbles, and then transported to the inner flow channel to be processed of the workpiece through the guide pipe to start processing; the processing time is 90 minutes, and the system automatically stops working after the processing is completed.

[0106] Step 4: Take out the workpiece, clean it with pure water ultrasonically for 10 minutes, replace it with new water and circulate the cleaning of the inner flow channel for ≥10 minutes until the water is clear and free of impurities, PH=7, then blow dry the inner flow channel with an air gun and dry the workpiece to complete the polishing of the complex and fine inner flow channel.

[0107] After processing, the parts were dissected and it was found that the powder sticking to the flow channel was significantly removed, the inner wall smoothness was improved, no particles or oxide scale remained, and the processing effect was consistent everywhere. After testing, the roughness of the inner flow channel was about 2.9μm.

[0108] Example 2

[0109] Implementation conditions: The workpiece is a machined spiral aluminum alloy inner flow channel with an inner diameter of 10 mm and an original roughness of about 3.2 μm.

[0110] Step 1: Prepare 5L of polishing solution in the working tank, add oxidant, corrosion inhibitor, surfactant and a small amount of additives in proportion, and mix evenly. The mass fraction of the polishing solution is 5%, the viscosity is 20cP, and the pH is 7.6.

[0111] Among them, the oxidants are sodium sulfate, sodium persulfate, sodium carbonate, sodium bicarbonate, sodium citrate and hydrogen peroxide (mass ratio is 2:3:2:1:1:3), accounting for 4.2% of the mass of the polishing solution; the corrosion inhibitors are sodium tripolyphosphate, benzotriazole and sodium carboxymethyl cellulose (mass ratio is 3:1:2), accounting for 0.7% of the mass of the polishing solution; the surfactants are coconut acid diethanolamide, disodium lauryl iminodiacetic acid and diethylhexanol (mass ratio is 1:2:1), accounting for 0.99% of the mass of the polishing solution; the auxiliary agent is ethylenediaminetetraacetic acid, accounting for 0.01% of the mass of the polishing solution.

[0112] Step 2: Fix the workpiece in the workpiece clamping device, connect the drain port, filtration system, circulation drive device, micro-nano bubble generating device, and guide tube through pipelines, and connect the guide tube to the inner flow channel of the workpiece to be processed. The guide end of the guide tube has a diameter of 18mm and fits tightly with the inlet of the inner flow channel of the workpiece to ensure that there is no leakage of liquid.

[0113] Step 3: Set the pressure of the polishing solution output by the circulation drive device to 0.7Mpa and the flow rate to 0.8m 3 / h, set the working temperature of the polishing solution to 30±10°C; set the micro-nano bubble generating device to make the micro-nano bubble content 12% and the micro-nano bubble size 100μm; set the workpiece rotation speed to 0.4m / s.

[0114] The power supply is started through the control system, the circulation drive device is started, the filtered polishing solution is extracted from the working tank, transported to the micro-nano bubble generating device through the pipeline system, injected with micro-nano bubbles, and then transported to the inner flow channel to be processed of the workpiece through the guide pipe to start processing. The processing time is 30 minutes. After the processing is completed, the system automatically stops working.

[0115] Step 4: Take out the workpiece, clean it with pure water ultrasonically for 10 minutes, replace it with new water and circulate the cleaning of the inner flow channel for ≥10 minutes until the water is clear and free of impurities, PH=7, then blow dry the inner flow channel with an air gun and dry the workpiece to complete the polishing of the complex and fine inner flow channel.

[0116] After processing, the parts were dissected and it was found that the powder sticking to the flow channel was significantly removed, the inner wall smoothness was improved, no particles or oxide scale remained, and the processing effect was consistent everywhere. After testing, the roughness of the inner flow channel was about 1.4μm.

[0117] Example 3

[0118] Implementation conditions: The workpiece is the inner flow channel of the additive manufacturing die steel, the inner diameter is reduced from 4mm to 2.5mm, and the pipe diameter is reduced from the original roughness of about 4.6μm.

[0119] Step 1: Prepare 2L of polishing solution in working 1, add oxidant, corrosion inhibitor, surfactant and a small amount of additives in proportion, and mix evenly. The mass fraction of the polishing solution is 3.6%, the viscosity is 4cP, and the pH is 6.5.

[0120] Among them, the oxidants are sodium sulfate, potassium persulfate, sodium citrate, ammonium chloride, sodium chloride, cerium nitrate and hydrogen peroxide (mass ratio is 1:2:1:4:1:1:2), accounting for 2.7% of the mass of the polishing solution; the corrosion inhibitors include aminoacetic acid, benzotriazole and polyethylene glycol (mass ratio is 3:1:1), accounting for 0.7% of the mass of the polishing solution; the surfactants include sodium dodecylbenzene sulfonate, monolauryl phosphate, coconut acid diethanolamide and polyoxyethylene polyoxypropylene copolymer (mass ratio is 1:1:1:1), accounting for 0.12% of the mass of the polishing solution; the additives are citric acid and malic acid (mass ratio is 1:2), accounting for 0.08% of the mass of the polishing solution.

[0121] Step 2: Fix the workpiece in the workpiece clamping device, connect the drain port, filtration system, circulation drive device, micro-nano bubble generating device, and guide tube through pipelines, and connect the guide tube to the inner flow channel to be processed of the workpiece. The guide end of the guide tube has a diameter of 5mm, and is connected from the 4.5mm or 2.5mm end of the workpiece. The guide tube fits tightly with the inlet of the inner flow channel to ensure that there is no leakage of liquid.

[0122] Step 3: Set the pressure of the polishing solution output by the circulation drive device to 0.2Mpa and the flow rate to 0.1m 3 / h, set the working temperature of the polishing solution to 30±10℃; set the micro-nano bubble generating device to make the micro-nano bubble content 7% and the micro-nano bubble size 80μm; set the reciprocating swing speed of the workpiece to 0.3m / s and the swing distance to 50mm.

[0123] The power supply is started through the control system, the circulation drive device is started, the filtered polishing solution is extracted from the working tank, transported to the micro-nano bubble generating device through the pipeline, injected with micro-nano bubbles, and then transported to the inner flow channel to be processed of the workpiece through the guide pipe to start processing. The processing time is 60 minutes. After the processing is completed, the system automatically stops working.

[0124] Step 4: Take out the workpiece, clean it with pure water ultrasonically for 10 minutes, replace it with new water and circulate the cleaning of the inner flow channel for ≥10 minutes until the water is clear and free of impurities, pH=7, then blow dry the inner flow channel with an air gun and dry the workpiece to complete the polishing of the complex and fine inner flow channel.

[0125] After processing, the parts were cut and it was found that the powder sticking to the flow channel was removed significantly, the inner wall was smoother, no particles or oxide scale remained, the processing effect was consistent everywhere, and there was no obvious edge collapse or over-throwing at the diameter change. The roughness of the inner flow channel was tested to be about 2.1μm.

[0126] Comparative Example 1

[0127] [Removal of micro-nano bubbles, oxidation > friction]

[0128] As a comparison group of Example 2, micro-nano bubbles were not added in Comparative Example 1, and other test conditions were the same.

[0129] Implementation conditions: The workpiece is a machined spiral aluminum alloy inner flow channel with an inner diameter of 10 mm and an original roughness of about 3.2 μm.

[0130] Step 1: Prepare 5L of polishing solution in the working tank, add oxidant, corrosion inhibitor, surfactant and a small amount of additives in proportion, and mix evenly. The mass fraction of polishing solution 2 is 5%, the viscosity is 20cP, and the pH is 7.6.

[0131] Among them, the oxidants are sodium sulfate, sodium persulfate, sodium carbonate, sodium bicarbonate, sodium citrate and hydrogen peroxide (mass ratio is 2:3:2:1:1:3), accounting for 4.2% of the mass of the polishing solution; the corrosion inhibitors are sodium tripolyphosphate, benzotriazole and sodium carboxymethyl cellulose (mass ratio is 3:1:2), accounting for 0.7% of the mass of the polishing solution; the surfactants are coconut acid diethanolamide, disodium lauryl iminodiacetic acid and diethylhexanol (mass ratio is 1:2:1), accounting for 0.99% of the mass of the polishing solution; the auxiliary agent is ethylenediaminetetraacetic acid, accounting for 0.01% of the mass of the polishing solution.

[0132] Step 2: Fix the workpiece in the workpiece clamping device, connect the drain port, filtration system, circulation drive device, micro-nano bubble generating device, and guide tube through pipelines, and connect the guide tube to the inner flow channel of the workpiece to be processed. The guide end of the guide tube has a diameter of 18mm and fits tightly with the inlet of the inner flow channel of the workpiece to ensure that there is no leakage of liquid.

[0133] Step 3: Set the pressure of the polishing solution output by the circulation drive device to 0.7Mpa and the flow rate to 0.8m 3 / h, set the polishing solution working temperature to 30±10℃; set the workpiece rotation speed to 0.4m / s.

[0134] The power supply is started through the control system, the circulation drive device is started, the filtered polishing solution is extracted from the working tank, transported through the pipeline system, and transported by the guide pipe to the inner flow channel of the workpiece to be processed, and the processing begins. The processing time is 30 minutes. After the processing is completed, the system automatically stops working.

[0135] Step 4: Take out the workpiece, clean it with pure water ultrasonically for 10 minutes, replace it with new water and circulate the cleaning of the inner flow channel for ≥10 minutes until the water is clear and free of impurities, PH=7, then blow dry the inner flow channel with an air gun and dry the workpiece to complete the polishing of the complex and fine inner flow channel.

[0136] After the processing is completed, the parts are dissected, and it can be seen that the processing effect is basically the same everywhere. There is no obvious powder sticking to the inner wall of the flow channel, and the inner wall smoothness is slightly increased, but a layer of gray oxide scale is attached to the surface, and the metallic luster is weak. The roughness of the inner flow channel is about 2.6μm after testing.

[0137] Compared with Example 2, the polishing solution in Comparative Example 1 remains unchanged, and a uniform amorphous oxide layer can be formed on the inner surface of the flow channel. However, the processing effect of Comparative Example 1 is poor because Comparative Example 1 lacks the assistance of micro-nano bubbles, and the micro-friction of the fluid is weakened, which is insufficient to match the oxidation capacity of the current polishing solution, and thus the formed amorphous oxide layer cannot be effectively stripped, so that the cyclic processing process of forming the amorphous oxide layer-stripping the amorphous oxide layer is interrupted, and thus the polishing effect is poor.

[0138] Comparative Example 2

[0139] [Change the polishing solution formula, oxidation > friction]

[0140] As a comparison group of Example 3, the polishing solution formula in Comparative Example 2 was changed, and other test conditions were the same.

[0141] Implementation conditions: The workpiece is the inner flow channel of the additive manufacturing die steel, the inner diameter is reduced from 4mm to 2.5mm, and the pipe diameter is reduced from the original roughness of about 4.6μm.

[0142] Step 1: Prepare 2L of polishing solution in working 1, add oxidant, corrosion inhibitor, surfactant and a small amount of additives in proportion, and mix evenly. The mass fraction of the polishing solution is 4.8%, the viscosity is 4cP, and the pH is 6.5.

[0143] Among them, the oxidants are sodium oxide, potassium persulfate, sodium citrate, ammonium chloride, sodium chloride, cerium nitrate and hydrogen peroxide (mass ratio of 2:2:1:4:1:1:4), accounting for 3.9% of the mass of the polishing solution; the corrosion inhibitors are aminoacetic acid, benzotriazole and polyethylene glycol (mass ratio of 3:1:1), accounting for 0.7% of the mass of the polishing solution; the surfactants are sodium dodecylbenzene sulfonate, monolauryl phosphate, coconut acid diethanolamide and polyoxyethylene polyoxypropylene copolymer (mass ratio of 1:1:1:1), accounting for 0.12% of the mass of the polishing solution; the additives are citric acid and malic acid (mass ratio of 1:2), accounting for 0.08% of the mass of the polishing solution.

[0144] Step 2: Fix the workpiece in the workpiece clamping device, connect the drain port, filtration system, circulation drive device, micro-nano bubble generating device, and guide tube through pipelines, and connect the guide tube to the inner flow channel to be processed of the workpiece. The guide end of the guide tube has a diameter of 5mm, and is connected from the 4.5mm or 2.5mm end of the workpiece. The guide tube fits tightly with the inlet of the inner flow channel to ensure that there is no leakage of liquid.

[0145] Step 3: Set the pressure of the polishing solution output by the circulation drive device to 0.2Mpa and the flow rate to 0.1m 3 / h, set the working temperature of the polishing solution to 30±10℃; set the micro-nano bubble generating device to make the micro-nano bubble content 7% and the micro-nano bubble size 80μm; set the reciprocating swing speed of the workpiece to 0.3m / s and the swing distance to 50mm.

[0146] The power supply is started through the control system, the circulation drive device is started, the filtered polishing solution is extracted from the working tank, transported to the micro-nano bubble generating device through the pipeline, injected with micro-nano bubbles, and then transported to the inner flow channel to be processed of the workpiece through the guide pipe to start processing. The processing time is 60 minutes. After the processing is completed, the system automatically stops working.

[0147] Step 4: Take out the workpiece, clean it with pure water ultrasonically for 10 minutes, replace it with new water and circulate the cleaning of the inner flow channel for ≥10 minutes until the water is clear and free of impurities, pH=7, then blow dry the inner flow channel with an air gun and dry the workpiece to complete the polishing of the complex and fine inner flow channel.

[0148] After processing, the parts were cut and it was found that the powder on the flow channel was removed obviously, but the smoothness of the inner wall did not change significantly. There were a few reddish-brown dots left locally, and there was no obvious collapse or over-throwing at the diameter change. The roughness of the inner flow channel was tested to be about 4.2μm.

[0149] Compared with Example 3, in Comparative Example 2, only the polishing solution is changed, and other processing conditions remain unchanged, but its processing effect is significantly worse. The reason is that the content and type of oxidant in the polishing solution in Comparative Example 2 are changed, and its oxidizing property is significantly enhanced, but the corrosion inhibition ability of the solution remains unchanged. The oxidizing property of the solution and the corrosion inhibition ability do not match, causing the amorphous oxide layer formed earlier to develop into a crystalline oxide layer, increasing the difficulty of friction peeling; at the same time, the fluid movement ability remains unchanged, which causes the micro-friction force of the processing system to not match the weak oxidizing force, making it difficult to remove the surface layer of the inner flow channel, resulting in poor polishing effect and even local corrosion.

[0150] It can be seen from the above that the polishing method of the present invention is a process of weak corrosion and micro-friction peeling cycle, and the two processes must be matched to achieve a good polishing effect.

[0151] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A complex micro-channel fluid polishing method based on the combined effect of weak oxidation and micro-friction, characterized in that: include: A polishing solution containing micro-nano bubbles is delivered into the inner flow channel of the workpiece to be polished according to preset parameters, and the workpiece to be polished is reciprocated and / or rotated according to preset parameters to achieve polishing of the inner flow channel of the workpiece; Among them, a uniform amorphous oxide layer is formed on the surface of the inner flow channel through the combined action of the oxidant, corrosion inhibitor and surfactant set in the polishing solution, and then the amorphous oxide layer is peeled off through the combined action force generated by fluid movement and micro-nano bubble explosion; the polishing of the inner flow channel of the workpiece is achieved by cyclically forming and peeling off the amorphous oxide layer.

2. The complex micro-channel fluid polishing method based on the combined effect of weak oxidation and micro-friction according to claim 1 is characterized in that: The polishing solution comprises an oxidant, a corrosion inhibitor, a surfactant, an auxiliary agent and pure water.

3. The complex micro-inner flow channel fluid polishing method based on the combined effect of weak oxidation and micro-friction according to claim 1 or 2, characterized in that: The oxidant accounts for 1wt% to 10wt% of the polishing solution, and includes one or more of copper sulfate, sodium sulfate, sodium persulfate, potassium persulfate, sodium oxide, sodium carbonate, sodium bicarbonate, sodium citrate, sodium chloride, ammonium chloride, sodium fluorosilicate, cerium nitrate, and hydrogen peroxide.

4. The complex micro-inner flow channel fluid polishing method based on the combined effect of weak oxidation and micro-friction according to claim 1 or 2, characterized in that: The corrosion inhibitor accounts for 0.1wt% to 1wt% of the polishing solution and includes one or more of sodium silicate, sodium metaphosphate, sodium tripolyphosphate, aminoacetic acid, succinic acid, benzotriaminoazole, polyethylene glycol, and sodium carboxymethyl cellulose.

5. The complex micro-inner flow channel fluid polishing method based on the combined effect of weak oxidation and micro-friction according to claim 1 or 2, characterized in that: The surfactant accounts for 0.01wt% to 1wt% of the polishing solution, and includes one or more of sodium dodecylbenzene sulfonate, monolauryl phosphate, lauryl ether phosphate, coconut oil diethanolamide, disodium lauryl iminodiacetate, diethylhexanol, tributyl phosphate, and polyoxyethylene polyoxypropylene copolymer.

6. The complex micro-inner flow channel fluid polishing method based on the combined effect of weak oxidation and micro-friction according to claim 1 is characterized in that: The polishing solution has a mass percentage of 1% to 10%, a viscosity of 1 to 30 cP, and a pH of 5 to 9.

7. The complex micro-channel fluid polishing method based on the combined effect of weak oxidation and micro-friction according to claim 1 is characterized in that: The volume fraction of the micro-nano bubbles in the polishing solution is 3% to 15%, and the size of the micro-nano bubbles is 0.01 μm to 100 μm.

8. The complex micro-channel fluid polishing method based on the combined effect of weak oxidation and micro-friction according to claim 1 is characterized in that: The method of delivering a polishing solution containing micro-nano bubbles into an inner flow channel of a workpiece to be polished according to preset parameters comprises: The pressure of the output polishing solution is 0.1Mpa~1.0Mpa, and the flow rate is 0.02m 3 / h~1m 3 / h, the working temperature of the polishing solution is 30±20℃.

9. The complex micro-channel fluid polishing method based on the combined effect of weak oxidation and micro-friction according to claim 1 is characterized in that: The step of causing the workpiece to be polished to reciprocate and / or rotate according to preset parameters includes: The reciprocating swing speed is 0.1m / s~1.2m / s, the swing distance is 10mm~100mm, and the rotation speed is 0.1m / s~1.0m / s.

10. The complex micro-inner flow channel fluid polishing method based on the combined effect of weak oxidation and micro-friction according to claim 1, characterized in that: In the process of conveying the polishing solution containing micro-nano bubbles into the inner flow channel of the workpiece to be polished, the polishing solution is circulated and the micro-nano bubbles are injected before being conveyed to the inner flow channel of the workpiece to be polished.

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