Finishing device and finishing method

Abstract

A finishing device comprising a thrust system (101), a sealing system (102), a transport pipeline system (103), and a recovery system (104). The sealing system (102) includes a piston (21) and a cylinder block (18) that fits onto the piston (21) and houses a finishing medium (8) for performing finishing operations. The transport pipeline system (103) transports the finishing medium (8) to a port of an internal flow path workpiece (34). The recovery system (104) includes a recovery container (35), a recovery pipeline (36), a reflux pipeline (37), a power assembly (130), and a control valve assembly (140). The control valve assembly (140) includes a first valve (38) and a second valve (39). The recovery container (35) is communicated with the internal flow path workpiece (34) via the recovery pipeline (36) and is communicated with the sealing system (102) via the reflux pipeline (37). The first valve (38) is adapted to the sealing system (102) and a low-pressure environment. The second valve (39) is located in the reflux pipeline (37) and is adapted to the recovery container (35) and the sealing system (102). The power assembly (130) is communicated with the recovery container (35). Through the synergistic effect of each member, high-speed replenishment of the finishing medium to the sealing system is achieved, and the efficiency of the finishing operation is ensured. Furthermore, a finishing method is provided.

Description

Technical Field

[0001] The present invention relates to the field of precision machining of internal flow paths, and particularly to a finishing device and a finishing method.

Background Art

[0002] Parts having a fine and complex internal flow path structure are extremely widely applied in industrial fields such as aerospace, ships, nuclear, automobiles, and molds. In particular, parts related to fluid power systems often have complex internal cavity structures such as fine flow paths, small-diameter deep holes, and the communication between fine flow paths and small-diameter deep holes. For example, fuel nozzles of various engines in aviation / aerospace / ships / automobiles, heat exchangers, hydraulic modules, oil passage control throttles, etc., perform functions such as fluid transportation, exchange, or hydraulic application.

[0003] Process technologies capable of machining fine and complex internal flow paths include precision machining, femtosecond / water jet guided / long pulse laser machining, spark machining, and additive manufacturing (3D printing), etc. Except for additive manufacturing technology, fine and complex internal flow path structures machined by other single processes are relatively simple, with a small ratio of length to diameter, and it is necessary to combine with other combined processes such as welding to machine fine and complex internal flow paths. Problems such as burrs, sharp corners at the corners, and steps at the machining joints occur in the fine and complex internal flow paths by precision machining. Residual particles attached and the "step" effect on the surface occur on the internal flow path surface by femtosecond laser machining. A remelting layer occurs on the internal flow path surface by water jet guided / long pulse laser and spark machining. Additive manufacturing (3D printing) is a technology that separates the component model with a complex three-dimensional structure into a two-dimensional structure and stacks and forms it layer by layer, enabling the integrated forming of complex and fine and complex internal flow path components. Therefore, its applications in industrial fields such as aerospace, automotive, and mold are increasing more and more. However, due to its own process characteristics such as temperature gradient and layer-by-layer forming in the component forming process, additive manufacturing technology generates powder particles semi-sintered or adhered on the internal flow path surface of the component and the "step" effect on the surface.

[0004] Burrs during machining, particles adhering and sintering in the internal channels during femtosecond laser machining, and adhering powder on the surface of the internal channels during additive manufacturing, etc. can affect the performance and safety of components. When burrs, adhering residue particles or adhering powder fall off due to the high-speed friction between the fluid flowing into the internal channel and the surface layer, they become extra substances and diffuse with the fluid, block the oil channel, or cause mechanical wear failures, leading to serious safety accidents. An inner surface with a large roughness is likely to become a fatigue crack source during long-term use, and in a high-temperature oil channel system, carbon accumulation is also likely to occur. The cutting edge traces on the surface of the channel during machining, the sharp corners of the corners or the steps at the machining joints, and the "step" phenomenon on the surface of the internal channels during femtosecond laser and additive manufacturing processes will cause turbulence, eddy currents and a sharp increase in fluid frictional drag during the fluid movement process, further causing fluid runaway, generating vibrations and reducing the service life of the components. The rough surface may generate a large number of cavitation bubbles in the fluid, affecting combustion and hydraulics, and may also cause cavitation corrosion. For the internal channels and communicating small holes of components made of specific materials such as hollow blades, fine cracks are likely to occur on the surface of the remelting layer, and the components fail early. Therefore, it is required to reduce the thickness of the remelting layer or not allow the appearance of the remelting layer.

[0005] Therefore, when machining the surface of the internal channels of fluid power components by technologies such as precision machining, femtosecond / water jet guided / long pulse laser machining, spark machining, additive manufacturing (3D printing), etc., it will bring adverse problems such as burrs, adhering powder, residues such as sintered particles, rough surfaces, and remelting layers. It is necessary to use appropriate surface finishing technologies to remove these adverse effects and meet the performance requirements of the products.

[0006] However, currently, since there is no technology that can effectively finish the surface of a fine and complex internal flow path, for the fine and complex internal flow path workpieces produced by additive manufacturing, their inner surface roughness generally only has the original average roughness Ra of 6.3 μm or more after additive manufacturing, and there are no products with the optimal surface roughness Ra of the internal flow path being 1.6 μm or less. For the fine and complex internal flow path workpieces processed by laser machining or spark machining, there are no products with the optimal surface roughness Ra of the internal flow path being 0.8 μm or less. Also, for the fine and complex internal flow path workpieces processed by machining, there are no products with the optimal surface roughness Ra of the internal flow path being 0.4 μm or less. However, currently, when the fine and complex internal flow path has complex irregular flow paths such as S-shaped bends, L-shaped bends, U-shaped bends, and O-shaped bends, it cannot be achieved by machining that can only perform linear feeding, and can only be achieved by methods such as additive manufacturing. Therefore, currently, there are no products with the optimal roughness Ra of the surface of the fine, irregular, and complex internal flow path by additive manufacturing being 1.6 μm or less.

Summary of the Invention

[0007] The object of the present application is to provide a finishing device and a finishing method.

[0008] In a first aspect, the present application submits a finishing device, the finishing device being a closed system comprising a thrust system and a piston and a cylinder block for accommodating a finishing medium that fits onto the piston and performs finishing, wherein the thrust system is communicated with one end of the piston to provide a driving force to the closed system to push the finishing medium out of the outlet end of the cylinder block; a transport pipeline system for transporting the finishing medium accommodated in the corresponding closed system to a port of an internal flow path work where finishing is to be performed, the upstream end of which is connected to the outlet end of the closed system and the downstream end of which discharges the finishing medium for finishing the internal flow path work; and a recovery system comprising a recovery container, a recovery pipeline, a reflux pipeline, a power assembly and a control valve assembly, wherein the control valve assembly comprises a first valve and a second valve, the recovery container is communicated with the work through the recovery pipeline and with the closed system through the reflux pipeline, the first valve is adapted to match the closed system and a low-pressure environment, the second valve is located in the reflux pipeline and is adapted to match the reflux container and the closed system, the power assembly is communicated with the recovery container and can provide power to the recovery container, and the recovery system can quickly reflux the finishing medium in the recovery system to the cylinder block.

[0009] In the technical solution according to the embodiment of the present application, the recovery system employs the first valve, the second valve and the synergistic effect between the two and the closed system, the recovery container, the reflux pipeline and the power assembly, thereby ensuring that both the reflux of the closed system and the discharge flow in which the finishing medium is transported from the closed system do not interfere with each other, and that the finishing medium accommodated in the recovery system can quickly reflux to the closed system.

[0010] In some embodiments, the first valve is a nozzle flapper valve, and the finishing device has a first state and a second state. Among them, in the first state, the finishing medium is transported from the sealed system to the transport pipeline system. The finishing medium contained in the sealed system acts on the nozzle of the nozzle flapper valve to close the nozzle flapper valve, and the second valve is closed. In the second state, the nozzle flapper valve is opened, and the transport of the finishing medium from the sealed system to the transport pipeline system is stopped so as to communicate the sealed system with the external low-pressure environment. The action of the finishing medium contained in the sealed system on the nozzle of the nozzle flapper valve is stopped, and the second valve is opened. The power assembly applies pressure to the recovery container until it reaches a first pressure. Thereby, there is a pressure difference between the recovery container and the sealed system, which is the pressure difference between the first pressure and the external low-pressure environment.

[0011] In some embodiments, the second valve is a solenoid valve, and the control valve assembly further includes a sensor for detecting the mass of the finishing medium in the recovery container. The solenoid valve is opened or closed according to the result of the mass detected by the sensor.

[0012] In some embodiments, the sensor is a gravity sensor, and the height of the recovery container is higher than the height of the sealed system.

[0013] In some embodiments, the recovery container is a transparent container, and the finishing medium contained therein is visible from the outside.

[0014] In some embodiments, the container wall of the recovery container has a volume scale line.

[0015] In some embodiments, a thermometer or a viscometer is provided in the recovery container.

[0016] In some embodiments, the finishing device further comprises a diagnostic device, and the diagnostic device includes a flow velocity and / or flow rate sensor and a pressure sensor for detecting the flow velocity and / or flow rate and pressure of the finishing medium.

[0017] In some embodiments, the piston has at least a first concave groove and a second concave groove from the top to the bottom, and the sealing system further comprises a sealing ring located between the piston and the cylinder block, including a first sealing ring provided in the first concave groove and a second sealing ring provided in the second concave groove, and the radial gap between the piston and the cylinder block is 1 mm to 2.5 mm.

[0018] In some embodiments, the first concave groove is formed separately, the upper surface of the piston is flat, and a cover plate is detachably provided thereon. The cover plate has an inclined surface on the outer periphery, and the inclined surface and the upper surface of the piston form a single-side inclined groove to constitute the first concave groove. The second concave groove is provided on the side wall of the piston. The material of the first sealing ring is a hard material, and the material of the second sealing ring is a soft material.

[0019] In some embodiments, the material of the first sealing ring satisfies that the flexural modulus is 1.9 GPa to 3.6 GPa, the elongation rate is 60% to 120%, and the Knoop hardness is 90 HK to 100 HK. The material of the second sealing ring satisfies that the flexural modulus is 0.2 GPa to 0.25 GPa, the elongation rate is 300% to 380%, and the flexural strength is 80 MPa to 100 MPa.

[0020] In some embodiments, the finishing medium includes a liquid phase and a solid phase. The viscosity of the liquid phase is less than 1000 cP. The solid phase includes abrasive grains. The workpiece to be finished is a fine internal flow path workpiece with a diameter of 3 mm or less and a length-to-diameter ratio of 50:1 or more.

[0021] In a second aspect, the present application provides a finishing method. The finishing method employs the finishing device described in the first aspect. The finishing medium includes a liquid phase and a solid phase. The viscosity of the liquid phase is less than 1000 cP. The solid phase includes abrasive grains. The workpiece to be finished is a fine internal flow path workpiece with a diameter of 3 mm or less and a ratio of length to diameter of 50:1 or more. The thrust system of the finishing device applies a predetermined pressure to the finishing medium such that the finishing medium flows through the fine internal flow path at a flow rate greater than 5 m / s. The flow rate at which the finishing medium flows into the fine internal flow path from one end thereof reaches the saturation value of the flow rate that can be accommodated by the diameter of the fine internal flow path, whereby the hydraulic pressure inside the internal flow path is in a state where pressure accumulates.

Brief Description of the Drawings

[0022] The above and other features, properties, and advantages of the present invention will become more apparent from the following description in connection with the accompanying drawings and examples. It should be noted that the accompanying drawings are all illustrative and not drawn under isometric conditions, and should not be regarded as limiting the scope of protection actually claimed by the present invention.

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0024] The following discloses various embodiments or examples for implementing the above-described theme technical solution. For the purpose of simplifying the disclosure, specific examples of each element and arrangement are described below, but these are merely examples and do not limit the protection scope of the present invention. "One embodiment", "an embodiment", and / or "some embodiments" mean features, structures, or special aspects related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "an embodiment" or "one embodiment" or "alternative embodiment" mentioned more than once at different positions in this specification does not necessarily refer to the same embodiment. Furthermore, some features, structures, or special aspects in expressions such as some embodiments, other embodiments, still other embodiments, etc. of the present application may be appropriately combined.

[0025] In this application, flowcharts are used to describe the operations performed by the system according to the embodiments of this application. It should be understood that the previous or subsequent operations are not necessarily precisely executed in order. Other operations can also be added to these processes, or operations of one or more steps can be removed from these processes.

[0026] Also, the average roughness described below refers to the case where a plurality of regions are selected and measured on the surface to be measured, and the average value is taken to obtain the average roughness of the measured surface. The optimal roughness described below refers to the case where a plurality of regions are selected and measured on the surface to be measured, and the minimum value is taken to obtain the optimal roughness of the measured surface. For example, when performing roughness measurement, for example, a certain region for roughness measurement is a pipeline segment with a length of 8 mm. In the pipeline to be measured, a plurality of pipeline segments with a length of 8 mm can be selected and measured to obtain the minimum value.

[0027] Parts with a fine and complex internal flow path structure are extremely widely applied in industrial fields such as aerospace, shipbuilding, nuclear, automotive, and mold. However, when machining the surface of the internal flow path of fluid power parts by current processing processes, such as precision machining, femtosecond / water jet guided / long pulse laser machining, spark machining, additive manufacturing (3D printing), etc., it brings adverse problems such as burrs, residues such as adhered powder and sintered particles, rough surfaces, and remelted layers. It is necessary to remove these adverse effects by appropriate surface finishing techniques to meet the performance requirements of the product.

[0028] Currently, for fine internal flow path work by additive manufacturing, there are no products with an optimal surface roughness Ra of the internal flow path of 1.6 μm or less. For fine internal flow path work by laser machining and spark machining, there are no products with an optimal surface roughness Ra of the internal flow path of 0.8 μm or less. Also, for fine internal flow path work by machining, there are no products with an optimal surface roughness Ra of the internal flow path of 0.4 μm or less. However, if the fine internal flow path has a special-shaped flow path structure such as S-shaped bending, L-shaped bending, U-shaped bending, or O-shaped bending, it cannot be achieved by linear feed machining and can only be achieved by additive manufacturing, etc. Therefore, currently, there are no products with an optimal surface roughness Ra of the internal flow path of 1.6 μm or less by additive manufacturing.

[0029] The inventor has conducted in-depth research, attempted and compared various finishing methods for different internal flow path surfaces, and discovered the following. When the internal flow path diameter of the part is large (>3 mm), the ratio of length to diameter is small (<50:1), and it extends in a substantially straight line, finishing can be performed by general methods such as manual polishing, chemical, electrochemical, plasma, magnetic force, magnetorheology, abrasive flow, water jet, and ultrasonic. However, for fine internal flow paths with a small internal flow path diameter (3 mm or less) and a large ratio of length to diameter (50:1 or more), (1) The abrasive flow technology was adopted, and the inner cavity was finished by a pressing and grinding mechanism using a finishing medium of a semi-solid ointment with high rigidity. However, the inventor found that for a creeping fluid in a state where the Reynolds number is extremely small, it is difficult to achieve uniform processing through a complex long-distance microchannel, and it is easy to be blocked at bends and dead ends. If forced to pass through, the channel may be deformed or cracked. Even if it barely passes through an internal channel with a length-to-diameter ratio of 50:1 or more, the pressure and flow rate rapidly decay as the fluid travel increases. The port of the internal channel becomes "excessive grinding and polishing", while the inside has too much pressure and flow rate loss and becomes "unpolished". In addition, a colloidal abrasive media insoluble in water tends to remain at the curves and dead ends of the internal channel and is difficult or impossible to be completely removed after processing. (2) The abrasive water jet technology, also known as fine abrasive slurry jet and high-speed flow / high-speed water particle finishing, was adopted. By applying hydraulic pressure to the water jet nozzle, a water jet with abrasives was ejected from the nozzle, and the surface material of the workpiece was washed away by its impact kinetic energy. However, due to the short distance between the water jet nozzle and the part surface, the abrasive water jet technology is not suitable for acting on a fine internal channel with a small inner diameter (3 mm or less) and a large length-to-diameter ratio (50:1 or more) of the internal channel. (3) Although the magnetic finishing technology is adopted, only a slight surface burnishing can be performed on the surface of the internal flow path with a diameter larger than 3 mm and extending in a substantially linear shape, and an effective surface finish cannot be performed on the fine and complex internal flow paths of S-shaped bending, L-shaped bending, U-shaped bending, O-shaped bending, and spiral bending with a diameter of 3 mm or less and extending three-dimensionally. The reasons are as follows. Magnetic finishing is a flexible process that uses relatively large-sized magnetic needle abrasives and is based on the principle that the convex and concave points on the surface are processed simultaneously under the action of an applied magnetic field. Therefore, only a slight improvement in surface burnishing can be performed on the surface by these flexible processing means. Even if the material removal amount is large, the "step" effect on the surface cannot be significantly improved, the surface roughness cannot be reduced, the powder and particles adhering to the surface cannot be significantly peeled off, and the burrs cannot be improved. Also, since this method is restricted by the movement of the magnetic field, it cannot handle the finishing of complex internal flow paths that extend three-dimensionally in parts. (4) Although the chemical finishing method is adopted, when the diameter of the internal flow path is small, the amount of corrosive solution that can be accommodated is small, the efficiency of the chemical finishing method is extremely low, and local reaction bubbles may accumulate and even prevent finishing. (5) Although the electrochemical, plasma finishing, and ultrasonic methods are adopted, it is difficult to arrange the electrodes along the narrow and three-dimensionally extending flow paths including S-shaped bending, L-shaped bending, U-shaped bending, O-shaped bending, and spiral bending, so the fine and complex internal flow paths cannot be finished.

[0030] Also, regarding (4) and (5), in methods such as chemical, electrochemical, and plasma finishing, various types of corrosion and altered layer defects may be caused to the fine structure of the flow path substrate, and the corrosive liquid and reaction gas also have an adverse impact on the environment and equipment. At the same time, (4) and (5) are also flexible processing means and have similar drawbacks to (3). Only a slight improvement in surface burnishing can be performed on the surface. Even if the material removal amount is large, the "step" effect on the surface cannot be significantly improved, the surface roughness cannot be reduced, and the powder, particles, and burrs adhering to the surface cannot be significantly peeled off.

[0031] As described above, as a result of intensive research, the inventor has found that in the above-mentioned processing method, for the structure of the fine internal flow path, it is difficult to finish the deep part of the fine internal flow path, and / or the finishing quality is not ideal. Therefore, it is difficult to apply it to the finishing process of the fine internal flow path.

[0032] Based on the above, the inventor further studied deeply and invented a surface finishing method for the fine internal flow path. A two-phase flow finishing medium with a liquid phase viscosity of less than 1000 cP is adopted. The flow velocity of the two-phase flow finishing medium in the fine internal flow path is made greater than 5 m / s, and the flow rate flowing into the inside at one end of the fine internal flow path reaches the saturation value of the flow rate that can be accommodated by the diameter of the fine internal flow path, so that the hydraulic pressure inside the internal flow path is in a state where pressure accumulates, thereby forming a means for the liquid to reach the saturation flow rate with respect to the fine internal flow path. That is, by the synergistic effect of the low-viscosity liquid phase, the fluid flow velocity of the finishing medium, and the saturation flow rate, the problem of the finishing process of the fine internal flow path is solved. The principle is described as follows. First, due to the synergistic effect of the low-viscosity liquid phase, the fluid flow velocity, and the saturation flow rate, the finishing medium can smoothly enter the fine and complex internal flow path and form a state similar to a non-Newtonian fluid in the fine and complex internal flow path. The fluid boundary layer is parallel to the surface of the internal flow path. The abrasive grains in the "knife-like" hard non-Newtonian fluid realize the targeted processing of the surface convex points by shear friction. Also, due to the synergistic effect of the above three factors, a micro-cutting force due to friction is obtained between the abrasive grains in the finishing medium and the surface of the fine and complex internal flow path. Therefore, without being limited by the material of the fine and complex internal flow path, the surface optimum roughness can be made to coincide with the range of the average contact length of the abrasive grain cutting edge, and even a super mirror surface quality with a surface optimum roughness Ra of 0.05 μm can be realized, breaking through the limitations of the principles of abrasive flow and water jet technology. The principle is described as follows. Since the cutting mechanism of the abrasive flow technology lies in the volume force generated by the pressing of the abrasive grains against the surface, when processing metals with low hardness and polymer flexible materials, dents and pits are likely to occur (Ra > 0.8 μm). The cutting force in the abrasive water jet technology is the erosion force caused by the impact of the abrasive grains against the surface. When processing soft metals, the surface is likely to be roughened (Ra > 0.8 μm).

[0033] In order to develop a finishing device corresponding to the above surface finishing method, the inventor has discovered the following. That is, the finishing device needs to adopt a sealed system for accommodating a finishing medium for performing finishing, and a transport pipeline system for transporting the finishing medium accommodated in the corresponding sealed system to the port of an internal flow path work where the finishing is to be performed.

[0034] Some finishing devices may adopt a plurality of sealed systems to communicate with each other by means of a work to realize the exchange of fluids. For example, two sealed systems and two transport pipeline systems are utilized, and each transport pipeline system transports the finishing medium accommodated in the corresponding sealed system to different ports of the internal flow path work where the finishing is to be performed. That is, one sealed system discharges the finishing medium to the work, and the other sealed system receives the finishing medium flowing out from the work. Also, when the finishing medium in one sealed system is used up, the other sealed system can continue to perform finishing on the work in the opposite direction to the previous one with the received finishing medium. That is, at this time, the other sealed system discharges the finishing medium to the work, while the sealed system with the used-up finishing medium receives the finishing medium flowing out from the work again. Thereby, it is ensured that the finishing medium accommodated in at least one sealed system can always be provided to the work, and the finishing work of the work can be continuously carried out without interruption, and an efficient finishing process is realized.

[0035] By the way, the inventor has conducted further research and discovered the following. That is, for some fine internal flow path works, the above two-way processing solution cannot be adopted, so a finishing device equipped with a plurality of sealed systems cannot be applied either. For example, the following configurations exist in fine internal flow path works: 1) Of the two ports of the fine internal flow path, only one port can perform a high-strength sealed connection, and the other port cannot perform a high-strength sealed connection. For example, since the port has an irregular shape or a thin-walled structure, the corresponding sealing joint cannot be machined, or it does not have the strength to withstand a high-strength sealed connection. 2) The fine internal flow path has a form of a specific throttling and guiding function like a Tesla valve, allowing only the fluid flow in one flow direction, and the fluid can only flow at a low speed and thus cannot flow in the other flow direction. 3) The fine internal flow path communicates with a group of densely arranged holes such as the film cooling holes of a single crystal blade of an aeroengine. One end is the inner cavity port of the single crystal blade, and the other end consists of densely arranged small holes in different irregular zones of the blade body.

[0036] For the above configuration, the two-phase flow finishing medium can only be fed into one predetermined port of the internal flow path and discharged from the other port, and cannot flow in the reverse direction. That is, for example, it is impossible to adopt a plurality of sealed systems to communicate with each other through the workpiece to realize the fluid exchange like a scheme of performing two-way processing on the workpiece in two sealed systems.

[0037] Regarding the one-way processing scheme, as a result of further research, it was found that since the flow rate of the finishing medium is fast, the consumption rate of the finishing medium by the sealed system is fast during the finishing process. Therefore, it is necessary to quickly perform automatic reflux and replenishment of the finishing medium to the sealed system.

[0038] In view of the above circumstances, the inventor conducted in-depth research and adopted a recovery system that employs a first valve, a second valve, and the synergistic effect of both with a sealed system, a recovery container, a reflux pipeline, and a power assembly, so as to ensure that both the reflux of the sealed system and the discharge flow through which the finishing medium is transported from the sealed system do not interfere with each other, and quickly reflux the finishing medium contained in the recovery system to the sealed system, realizing high-speed replenishment of the finishing medium to the sealed system and ensuring the efficiency of the finishing process.

[0039] The surface finishing device for the internal flow path disclosed in the embodiments of the present application contributes to solving the problem that it is impossible to efficiently process a fine internal flow path workpiece with a small internal flow path diameter (3 mm or less), a large ratio of length to diameter (50:1 or more), and only one-way flow processing of the finishing medium can be performed. However, it is understood that what is disclosed in the embodiments of the present application can be applied not only to the described surface finishing method and fine internal flow path workpieces that can only perform one-way processing, but also to other fluid processing methods and internal flow path workpieces.

[0040] It should be explained that the terms "diameter" and "length" in the context mean equivalent diameter and equivalent length, and the ratio of length to diameter is the ratio of equivalent length to equivalent diameter. Regarding the equivalent diameter, the cross-sectional shape of the internal flow path may be circular, elliptical, etc. whose cross-sectional contour is a closed curve (non-broken line). The cross-sectional shape of the internal flow path may also be rectangular, triangular, etc. whose cross-sectional contour is a closed broken line. The cross-sectional contour is composed of an arbitrary closed curve (non-broken line) or a closed broken line, and since the cross-sectional contour is an irregular shape, the equivalent diameter is introduced, and the equivalent diameter is defined as follows. For any cross-sectional shape, an ideal circle equal to the actual cross-sectional area of the arbitrary cross-sectional shape is taken, and the diameter of this ideal circle is the equivalent diameter. The equivalent length refers to the total stroke that the fluid in the internal flow path actually flows between two ports of the internal flow path.

[0041] First, in order to understand the effect of the finishing device of the present application, a surface finishing method for a fine internal flow path to which the finishing device can be applied will be described.

[0042] Referring to FIG. 1, the present application provides a surface finishing method for an internal flow path, and the method includes using a finishing medium of a liquid-solid two-phase flow with a liquid-phase viscosity less than 1000 cP and a solid phase being abrasive grains, and A predetermined pressure is applied to the finishing medium so that the finishing medium flows in the fine internal flow path at a flow velocity greater than 5 m / s. The flow rate at which the finishing medium flows into the inside from one end of the fine internal flow path reaches the saturation value of the flow rate that can be accommodated by the diameter of the fine internal flow path, and the hydraulic pressure inside the internal flow path is in a state where the pressure accumulates.

[0043] The liquid here has the property that its viscosity is less than 1000 cP. In this application, all descriptions regarding viscosity values refer to the Ubbelohde viscosity at room temperature (around 25°C). The optimal value of the viscosity of the liquid phase corresponding to the finishing method for fine internal flow paths with different materials, dimensions, and initial average roughness can be obtained by continuously increasing the viscosity based on the lower limit value. Currently, the lower limit value of the viscosity in the examples is about 50 cP. Through a large amount of test data, the inventor has obtained that for fine internal flow paths of general materials such as titanium alloys, superalloys, steels, ceramics, aluminum alloys, and polymer materials, in order to reach the target value of roughness after finishing, the viscosity of the liquid phase needs to be at least 50 cP. Here, the critical value of 1000 cP is not generally the optimal value either, but the limit value at which the finishing medium can flow continuously, smoothly, and stably through the fine internal flow path.

[0044] Taking the aqueous liquid phase as an example for the liquid phase described in the examples, a certain thickener is added to deionized water so that the aqueous liquid has a certain viscosity. The beneficial effect of using an aqueous liquid is that it is low-cost and easy to obtain, environmentally friendly, and the finishing medium is easy to clean after finishing. However, it is understood that the liquid phase here is not limited to aqueous liquids as long as the viscosity μ is less than 1000 cP.

[0045] The material of the solid-phase abrasive grains may be a general abrasive grain material such as carbide ceramics including silicon carbide, tungsten carbide, etc., oxide ceramics including aluminum oxide, zirconium oxide, cerium oxide, etc., nitride ceramics including boron nitride, chromium nitride, etc., and natural minerals including diamond / sand, mica, quartz, tourmaline, etc. Preferably, it may be one or more combinations of diamond / sand and oxide ceramics.

[0046] When selecting the particle size and mass concentration of the abrasive grains, it is common to gradually increase based on the lower limit value to obtain the range of the optimal value. When the particle size and mass concentration of the abrasive grains are below the lower limit value, the expected finishing effect cannot be achieved, that is, the fine internal flow path cannot achieve the target value of the surface roughness. The principle is that if the particle size is too small, the mass of the abrasive grains themselves is too low to generate sufficient kinetic energy to realize effective polishing and grinding. If the mass concentration is too small, the probability that the processing points on the surface are ground decreases and effective polishing and grinding cannot be realized. The selection of the lower limit value is generally conservative. For example, it is possible to conservatively select any lower limit value on the premise of not exceeding the upper limit value of the particle size. The lower limit of the ratio of the internal flow path diameter to the particle size of the abrasive grains is usually 20, that is, it is necessary to ensure that the internal flow path diameter does not become clogged when at least 20 abrasive grains pass in parallel. That is, the upper limit of the particle size of the abrasive grains is usually 1 / 20 of the internal flow path diameter, and the lower limit value of the abrasive grains is generally 1 / 5 of the upper limit value. The lower limit value of the mass concentration of the abrasive grains is generally 10 g / L, and the selection of the lower limit value is generally relatively conservative because, due to the relatively high pressure of the system, if abrasive grain clogging occurs, it may cause the waste of the workpiece and the system, or cracking and explosion. Therefore, until a significant flow resistance is generated due to the particle size of the abrasive grains being too large or the mass concentration being too high, causing a decrease in the flow velocity and flow rate, and the mutual collision between the abrasive grain particles affecting the flow velocity and reducing the flow velocity, flow rate, and grinding effect, based on a predetermined lower limit, the particle size and mass concentration of the abrasive grains are gradually increased, that is, the optimal value can be obtained by testing based on the lower limit value.

[0047] A predetermined pressure is applied to the finishing medium so that the finishing medium flows through the fine internal flow path at a flow velocity greater than 5 m / s. The predetermined pressure here means the pressure that enables the finishing medium to flow through the inside of the fine internal flow path at a flow velocity greater than 5 m / s even in the initial state of the finishing process. As the finishing progresses, the surface roughness of the internal flow path decreases, and under the same pressure conditions, the flow velocity of the finishing medium in the fine internal flow path becomes faster and faster. It can be understood that since the realized flow velocity is within a certain range, the predetermined pressure here is a concept of range and does not mean that only a specific value can be applied to the finishing medium. To measure the flow velocity of the finishing medium inside the fine internal flow path, immersion measurement cannot be adopted, otherwise, there is a risk that the abrasive grains will damage the sensor probe. The method of ultrasonic velocity measurement can be adopted, and indirect measurement can also be carried out by using the Hagen-Poiseuille's law (the following formula) of viscous fluids. In the formula, D is the internal flow path diameter, l is the length of the fine internal flow path, p is the pressure difference acting on both ends of the fine internal flow path, that is, the hydraulic pressure p, Re is the Reynolds number, um is the flow velocity of the liquid phase in the aqueous two-phase flow, ρl is the density of the liquid phase, and the flow velocity of the liquid phase is approximately equal to the flow velocity of the finishing medium.

Number

[0048] The flow velocity of the finishing medium is greater than 5 m / s and is based on the critical conditions for theoretically forming a non-Newtonian fluid and the critical values obtained by the inventor through long-term practice. According to the engineering fluid mechanics materials (for example, the book materials: Yang Shuren, Wang Zhiming, He Guangyu, etc., Engineering Fluid Mechanics [M]. Petroleum Industry Press, 2006), when the viscosity of pure water is 1 cP, the critical flow velocity of the non-Newtonian fluid reaches more than 16.6 m / s. However, the lower limit value of the viscosity of the liquid phase in this embodiment is 50 cP, which is greater than 1 cP. Therefore, the critical flow velocity of the non-Newtonian fluid is less than 16.6 m / s. At the same time, combining the practical results, the inventor found that an ideal processing effect cannot be obtained when the flow velocity is less than 5 m / s. Therefore, the critical value is set to 5 m / s.

[0049] The flow rate at which the finishing medium flows into the interior at one end of the fine internal flow path reaches the saturation value of the flow rate that can be accommodated by the diameter of the fine internal flow path, and the hydraulic pressure inside the internal flow path is in a state where pressure accumulates, that is, in a state of so-called saturated flow rate in this field.

[0050] The saturation value of the accommodation flow rate and the state of saturated flow rate here mean that when the fluid flows into the pipe, it fills the pipe cross-section, and the pipe cross-section accommodates the fluid molecules in parallel to the maximum extent.

[0051] It can be understood that the beneficial effects of the finishing method of the above embodiments are as follows.

[0052] Adopt a liquid with a viscosity of less than 1000 cP in the liquid phase of the finishing medium, increase the flow velocity in the fine internal flow path of the two-phase flow finishing medium to be greater than 5 m / s, and make the flow rate flowing into the inside at one end of the fine internal flow path reach the saturation value of the flow rate that can be accommodated by the diameter of the fine internal flow path. Make the liquid pressure inside the internal flow path in a state where pressure accumulates, and form a means for the liquid to reach the saturation flow rate with respect to the fine internal flow path. That is, by the synergistic effect of the low-viscosity liquid phase, fluid flow velocity, and saturation flow rate, solve the problem of difficult finishing of the fine internal flow path. Describe its principle. First, due to the synergistic effect of the low-viscosity liquid phase, fluid flow velocity, and saturation flow rate, the finishing medium is in a state of low viscosity and high flow velocity, so it can smoothly enter the fine internal flow path and form a non-Newtonian fluid state inside the fine internal flow path. The fluid boundary layer is parallel to the surface of the internal flow path, and the abrasive grains in the hard liquid phase like a "blade" can realize the target processing of surface convex points through shear friction, and the problem that only slight polishing can be achieved when the convex and concave points on the surface during flexible processing are processed simultaneously is overcome in principle. At the same time, due to the micro-cutting force caused by the friction between the abrasive grains of the finishing medium and the surface of the fine internal flow path, without being limited by the material of the fine internal flow path, the optimal surface roughness that matches the average contact length range of the abrasive grain cutting edge can be obtained, breaking through the limitations of the principles of abrasive flow and water jet technology. Describe its principle. Since the cutting mechanism of abrasive flow technology lies in the volume force generated by the pressing of abrasive grains on the surface, when processing metals with low hardness and polymer flexible materials, dents and pits are likely to occur (Ra>0.8μm). The cutting force in abrasive water jet technology is the erosion force caused by the impact of abrasive grains on the surface. When processing soft metals, the surface is likely to be roughened (Ra>0.8μm). Also, in the hydrodynamic shape adaptive (conformal) processing method with low viscosity and high flow velocity, positions that do not conform to fluid mechanics such as steps, sharp corners, and geometric contour curvatures on the surface of the internal flow path are more polished, and the corners, sharp edges, contour curvature of the internal flow path, and hole shape achieve geometric streamline shaping, further improving the fluid motion performance of the internal flow path. Also, the above embodiment proposed that the critical flow velocity for realizing a hard non-Newtonian fluid like a blade by utilizing the flow velocity of the finishing medium and realizing the target processing of surface convex points through the shear friction of abrasive grains is 5 m / s.

[0053] Regarding the processing time in the fine internal flow path of the finishing medium, the finishing medium may finish the fine internal flow path within a reference period until the surface optimum roughness of the fine internal flow path reaches the target value. Here, the reference period may be a predetermined continuous period, or may be a plurality of intermittent periods, or after a non-predetermined continuous period after the start, when it is detected that the flow velocity and flow rate of the finishing medium reach the flow velocity and flow rate at which the surface optimum roughness of the fine internal flow path reaches the target value, the finishing process may automatically stop. For example, as described above, in some embodiments, after starting the processing, the surface optimum roughness is indirectly obtained by characterizing the flow velocity or flow rate of the finishing medium in the fine internal flow path, and when the flow velocity or flow rate value reaches a predetermined value, the corresponding surface optimum roughness reaches the target value. At this time, the finishing process is stopped manually or automatically. The meaning of the surface optimum roughness reaching the target value here does not necessarily require directly measuring the surface optimum roughness, and it may be indirectly characterized. For example, as introduced above, it may be a method of characterizing the flow velocity, flow rate, etc. of the finishing medium inside the fine internal flow path. The above target value refers to the set surface optimum roughness value, and generally refers to the requirement for the final surface optimum roughness of the fine internal flow path. However, continuing the finishing after the above finishing step is not excluded, and what is set at this time is not the requirement for the final surface optimum roughness.

[0054] In short, the finishing method introduced in the above embodiments constructs a hydraulic system at both ends of the internal flow path to be processed, combines means such as the use of a low-viscosity, high-speed solid-liquid two-phase fluid, reaching the saturated flow rate of the internal flow path to be processed, and the fine cutting mechanism generated by the abrasive grains in the two-phase flow rubbing the internal flow path surface at high speed, to solve the long-existing problem in the industry of difficult finishing of fine internal flow paths with a diameter of 3 mm or less and a length-to-diameter ratio of 50:1 or more.

[0055] Referring to what is shown in FIGS. 2 to 4, in some embodiments, the present application provides a finishing device 100 including a thrust system 101, a sealing system 102, a transport pipeline system 103, and a recovery system 104. The sealing system 102 includes a piston 21 and a cylinder block 18 that fits onto the piston 21 and houses a finishing medium 8 for performing finishing. The thrust system 101 is communicated with one end of the piston 21 and provides a driving force to the piston 21 to push the finishing medium 8 out from the outlet end 190 of the cylinder block 18. The transport pipeline system 103 transports the finishing medium 8 accommodated in the corresponding sealing system 102 to a one-way processing port of an internal flow path work 34 where finishing is performed. For example, the single sealing system 102 and the transport pipeline system 103 shown in FIG. 2 correspond to a one-way processing port of the work 34. The one-way processing port here refers to a predetermined port in the work 34 for the finishing medium to be fed in as introduced above. Referring to what is shown in FIG. 4, in some embodiments, the finishing device may further include a jig 31. The jig 31 has at least two ports 310 and corresponds to at least one inlet and at least one outlet of the work 34. As can be seen from the above, during the finishing process, the finishing medium always flows in one direction, that is, it enters from the left port 310 and flows out from the right port 310. The left port 310 corresponds to the one-way processing port of the work 34 described above and is connected to the transport pipeline system 103, while the right port 310 is connected to the recovery system 104.

[0056] The recovery system 104 includes a recovery container 35, a recovery pipeline 36, a reflux pipeline 37, a power assembly 130, and a control valve assembly 140. The control valve assembly 140 includes a first valve 38 and a second valve 39. The recovery container 35 communicates with the workpiece 34 via the recovery pipeline 36 and communicates with the sealed system 102 via the reflux pipeline 37. The first valve 38 is adapted to the sealed system 102 and the low-pressure environment. Here, the low-pressure environment is defined based on the high pressure generated by the power assembly 130. The low-pressure environment may be, for example, the open pressure of the indoor environment where the finishing device 100 is disposed. The second valve 39 is located in the reflux pipeline 37 and is adapted to the reflux container 35 and the sealed system 102. The power assembly 130 communicates with the recovery container 35 and can provide pressure to the recovery container 35.

[0057] The beneficial effects of the above-described embodiments are as follows. That is, by providing a recovery system that employs the synergistic action of the first valve 38, the second valve 39, and both of them with the sealed system 102, the recovery container 35, the reflux pipeline 37, and the power assembly 130, it is ensured that both the reflux of the sealed system and the discharge flow in which the finishing medium is transported from the sealed system do not interfere with each other, and the finishing medium accommodated in the recovery system is quickly refluxed to the sealed system, realizing high-speed replenishment of the finishing medium to the sealed system and ensuring the efficiency of the finishing process.

[0058] Referring to what is shown in FIGS. 2 to 4, in some embodiments, the specific forms of the synergistic action of the first valve 38, the second valve 39, and the sealed system 102, the recovery container 35, the reflux pipeline 37, and the power assembly 130 are as follows. That is, the finishing device 100 has a first state and a second state, and the first valve 38 is a nozzle flapper valve, among which, In the first state, i.e., in the process of performing finishing processing, the finishing medium is transported from the single closed system 102 to the transport pipeline system 103 up to the one-way processing port of the workpiece 34. In the closed system 102, since the pressure for pushing the contained finishing medium 8 by the piston is large, the first valve 38 provided at the top of the cylinder block 18 is also pushed by the finishing medium 8 with a large pressure. And the nozzle of the first valve 38 receives the action of the pressure of the finishing medium 8, discharges the finishing medium, and pushes the flapper. As a result, the nozzle flapper valve is closed, the first valve 38 is closed, and at this time, the second valve 39 is also in a closed state. The flow direction of the finishing medium 8 is discharged from the closed system 102 to the workpiece 34 and then discharged from the workpiece 34 to the recovery container 35 for storage.

[0059] In the second state, since the finishing medium that the closed system 102 can accommodate is limited, after all the finishing medium in the cylinder block is pushed out by the piston, the transportation of the finishing medium from the closed system to the transport pipeline system is stopped. At this time, since the action of the finishing medium contained in the closed system on the nozzle of the first valve 38 is stopped, the nozzle of the first valve 38 does not discharge the finishing medium, the flapper in the nozzle flapper valve returns to the position where it opens the first valve 38, and the closed system 102 communicates with the external low-pressure environment. At this time, the second valve 39 is in an open state because the sensor detects the mass threshold in the recovery container. The recovery container 35 and the closed system 102 are directly communicated via the reflux pipeline 37. The power assembly 130 applies pressure to the recovery container 35 until the first pressure is reached. As a result, there is a pressure difference between the first pressure and the external low-pressure environment between the recovery container 35 and the closed system. Under the action of this pressure difference, the finishing medium contained in the recovery container 35 quickly refluxes to the closed system via the reflux pipeline 37. The specific structure of the power assembly 130 may be, but is not limited to, an air compressor or an air pump device 40 and a pressure pipe 41 for increasing the pressure of the recovery container 35.

[0060] Adopting the nozzle flapper valve solution to achieve the switching between the first state and the second state is surely effective. The principle is described as follows. In the nozzle flapper valve, the nozzle can adapt to high pressure and has sufficient strength, sealing and jet performance for the high-speed finishing medium, so it can effectively push the flapper, ensuring the high sensitivity and certainty of the state switching of the nozzle flapper valve.

[0061] Referring to what is shown in FIGS. 2 and 3, in some embodiments, the second valve 39 is a solenoid valve, and the control valve assembly 140 further includes a sensor 42 for detecting the mass of the finishing medium 8 contained in the recovery container 35, and the second valve 39 is opened or closed according to the detection result by the sensor 42. For example, when in the above second state, when the detection signal detected by the sensor 42 is fed back to the control unit, the control unit determines that the mass of the finishing medium 8 contained in the recovery container 35 exceeds the threshold value. This threshold value is usually set to 85% - 98% of the total mass of the finishing medium in the closed system. The reason is as follows. That is, since there is a possibility that the finishing medium remains in any of the first valve 38, the transport pipeline system 103, and the closed system 102, a certain reserve space for the mass loss of the finishing medium is required. Also, before all the finishing medium in the closed system is extruded, the second valve 39 of the solenoid valve is opened, and in order to prevent a reverse flow accident in which the closed system 102 transports the high-pressure finishing medium to the recovery system through the recovery pipeline 36, it should also be avoided that the threshold value is set too small. Regarding the specific values within the range of 85% - 98%, they vary depending on the remaining mass of the finishing medium in the first valve 38, the transport pipeline system 103, and the closed system 102, and may be obtained through on-site tests and adjustments. For example, a large threshold value, such as 98%, is set first. If it is observed that there is no reflux when the first valve 38 is opened, the threshold value can be correspondingly reduced, and finally the actual threshold value can be obtained. Further, usually, after reaching the threshold value, the control unit may issue a command to open the second valve 39, which is a solenoid valve, with a 3-second delay. The reason for the 3-second delay is to prevent a reverse flow accident in which the second valve 39 of the solenoid valve is opened before all the finishing medium in the closed system is extruded, and the closed system 102 transports the high-pressure finishing medium to the recovery system through the recovery pipeline 36. Since the control by the solenoid valve is sensitive and accurate, it is further ensured that the reverse flow in the closed system and the discharge flow in which the finishing medium is transported from the closed system do not interfere with each other.In some embodiments, the sensor 42 is a gravity sensor, and the height of the recovery container 35 is higher than the height of the closed system 102. By doing so, the reliability of the detection results by the gravity sensor can be fully utilized, and since the recovery container 35 is higher than the closed system 102, the finishing medium 8 can promote reflux due to the action of gravity, and the efficiency of reflux is further improved.

[0062] Subsequently, referring to what is shown in FIG. 2, in some embodiments, the recovery container 35 is a transparent container, and the finishing medium accommodated therein is visible from the outside. Specifically, the transparent material may be a material such as transparent glass or acrylic resin. By using a transparent container visible from the outside as the recovery container 35, the operator can directly observe characteristic information such as the amount of bubbles on the surface of the finishing medium in the recovery container 35, the color of the liquid phase, and the uniform dispersion state of the abrasive solid phase. Therefore, the proportion of the liquid phase and the bubble gas phase in the finishing medium can be judged respectively, the color of the liquid phase can be judged to determine whether organic components such as thickeners have deteriorated and affected the processing effect, or whether the requirements of environmental protection are met. Furthermore, it can be judged whether the finishing medium 8 in the closed system 102 has caused phenomena such as aggregation or sedimentation of the abrasive solid phase, and the state of the finishing medium and the finishing process can be monitored intuitively and effectively.

[0063] In addition, in some embodiments, the container wall of the recovery container 35 has a volume scale line 43. By doing so, the volume of the finishing medium entering the recovery container 35 per unit time can be judged, and further the flow rate of the finishing medium on the workpiece 34 can be judged. Also, by monitoring the change in the flow rate, it is possible to diagnose whether the finishing quality of the internal flow path has reached the required flow rate and whether fluctuations in the speed have occurred. Moreover, the volume amounts of the solid, liquid, and gas phases in the finishing medium can be judged more accurately by the scale.

[0064] In addition, a thermometer or a viscometer may be provided in the recovery container 35 to judge whether the temperature and viscosity of the finishing medium have changed significantly.

[0065] Since the recovery container 35 is under low pressure during the operation of the finishing device 100 and does not usually receive a large pressure like the closed system 102, the installation of the recovery container 35 may also serve as a means for the operator to intuitively monitor the finishing medium and the state changes during the finishing process.

[0066] In some embodiments, the ratio of the length to the diameter of the transport pipeline system 103 is greater than 10:1, and the caliber of the outlet end is greater than 3 mm. The transport pipeline system 103 has a multi-stage pipeline, and the ratio of the cross-sectional area of the front-stage pipeline to that of the rear-stage pipeline of two adjacent stages of the pipeline is greater than 1.

[0067] The thrust system 101 includes a vertical plunger pump 5. The vertical plunger pump 5 is connected to the piston 21 so that the piston 21 can move along the vertical direction with respect to the cylinder block 18, thereby providing a driving force. The multi-stage pipeline includes a first-stage pipeline 22 and a second-stage pipeline 23 connected adjacent to the downstream of the first-stage pipeline. The first-stage pipeline has a bend structure connected to the outlet end 190 of the cylinder block 18, and the bend structure is connected to the horizontally extending second-stage pipeline 23. In this way, a combination of a vertical structure and a horizontal structure is realized.

[0068] The thrust system 101 may be a hydraulic system. As shown in FIG. 2, it includes a motor 1, a hydraulic working oil tank 2, a hydraulic pump 3, a pressure boosting device 6, a vertical plunger pump 5, and an oil pipe 4. The motor 1 drives the hydraulic pump 2 to extract hydraulic working oil at a certain pressure from the oil tank 2. The pressure oil boosted by the pressure boosting device 6 is transported to the vertical plunger pump 5. The vertical plunger pump 5 is connected to the piston 21 via a ball head 13 to drive the piston 21 to push the finishing medium 8 out from the discharge end 190 of the cylinder block 18. By adopting a hydraulic system driven by a motor, not only is the thrust large, but also the accuracy of the thrust is high.

[0069] Corresponding to the configuration of the vertical plunger pump 5, the closed system 102 should also be configured vertically, that is, the moving direction of the piston 21 relative to the cylinder block 18 is the relative moving direction along the vertical direction. However, since the corresponding processing workpiece 34 needs to be horizontal, the direction can be changed by the transport pipeline system.

[0070] The cylinder block 18 has its space regulated by the bottom plate and the top plate 19, and the bottom plate and the top plate 19 may be connected to the cylinder block 18 via bolts 7. The finishing medium 8 is accommodated in the space between the piston 21 and the top plate 19, and the opening of the top plate 19 is the outlet end 190 of the closed system 102. The ratio of the diameter of the cylinder block 18 to the outlet end 190 is 10 to 32, thereby further increasing the pressure of the finishing medium. Referring to what is shown in FIG. 4, in some embodiments, the ratio of the cross-sectional area of the first-stage pipeline 22 to the second-stage pipeline 23 may be 1.2 to 1.8. In this way, the finishing medium can be stably and gradually pressurized, and the saturated flow rate can be continuously maintained. In some embodiments, the multi-stage pipeline may further include a third-stage pipeline 32 connected adjacent to the downstream of the second-stage pipeline 22, and the ratio of the cross-sectional area of the second-stage pipeline 22 to the third-stage pipeline 32 is 1.2 to 1.8. As shown in the figure, the length of the third-stage pipeline 32 may be short, like a joint. By adopting a three-stage pipeline and a configuration where the ratio of the cross-sectional area per stage is 1.2 to 1.8, it is possible to stably and gradually increase the pressure, continuously maintain the saturated flow rate, ensure the conditions for providing a stable pressure to the finishing medium, and also ensure the strength, reliability, and service life of the transport pipeline system 103.

[0071] Referring to what is shown in FIG. 4, in some embodiments, the finishing device may include a jig 31, the jig 31 having at least two ports 310 corresponding to at least one inlet and at least one outlet of the workpiece 34. The jig 31 is stably fixed and attached by a three-jaw chuck 33 on the table, and the workpiece 34 is clamped and fixed inside the jig 31 by the clamp bolts 30 of the jig. The ratio of the caliber of the third-stage pipeline 32 to the cross-sectional area of the port of the jig 31 connected thereto may be 1.2 to 2.2, and the beneficial effect thereof is similar to the above, and it can stably increase the pressure gradually and continue to maintain the saturated flow rate. The following may be noted. That is, the upper limit value of the ratio of the cross-sectional area of the third-stage pipeline 32 to the port of the jig 31 connected thereto is set to 2.2, and it may be higher than the upper limit value of 1.8 of the proportionality of the cross-sectional areas of the pipelines. The reason will be described. That is, since the jig 31 is usually frequently replaced and the requirement for the service life is not as strict as that of the pipeline, the upper limit of the proportionality of the cross-sectional area can be set larger. In some embodiments, the ratio of the cross-sectional area of the port of the jig to the port of the workpiece 34 should be greater than 1 and less than or equal to 10, and both may be sealed with epoxy resin. When the ratio is greater than 1, the internal flow path of the workpiece can reach the saturated flow rate. However, if it becomes too large, the relief pressure at the port of the workpiece 34 will increase, and the requirements for the strength and sealing of the connection between the port and the workpiece will become strict, and as a result, the inventor has discovered that safety accidents such as breakage of the connection location may occur. Therefore, the inventor has discovered that the ratio should be less than or equal to 10. It is understood that many ports 310 applicable to the internal flow paths of workpieces with different calibers may be provided on the jig 31 for reserve. When using one of the ports, the other unused ports may be connected and blocked by bolts. The clamp bolts 30 of the jig 31 include an upper clamp bolt and a lower clamp bolt of the jig, and can clamp workpieces 34 of different specifications and sizes, and adjust the ports of the jig and the ports of the internal flow path of the workpiece to be on the same axis as the port of the jig and the ports of the multi-stage pipeline.

[0072] By adopting the multi-stage pipeline transportation pipeline system introduced in the above embodiments, the configuration of the thrust system combined with a hydraulic pump and a vertical plunger pump, and the combined form of vertical and horizontal types, even when providing a thrust of 50 MPa or more, high accuracy can be achieved (the error is 0.01 MPa), and during operation, the pressure fluctuation is small, within the range of ±0.1%, and it is found that the finishing method introduced above can be fully and effectively realized.

[0073] Referring to what is shown in FIGS. 2 and 3, for the closed system 102, since it is necessary to provide a large pressure to the finishing medium, the sealing problem between the piston 21 and the wall of the cylinder block 18 is particularly important, and at the same time as ensuring the sealing performance, the inventor has discovered that it is necessary to ensure the smooth movement of the piston 21 along the inner wall of the cylinder block 18.

[0074] The piston 21 has at least a first concave groove 211 and a second concave groove 210 in the direction from the top to the bottom. The closed system 102 further includes a sealing ring located between the piston 21 and the cylinder block 18, including a first sealing ring 17 provided in the first concave groove 211 and a second sealing ring 170 provided in the second concave groove 210. The radial gap between the piston 21 and the cylinder block 18 is 1 mm to 2.5 mm. By adopting the configuration of multi-stage concave grooves, multi-stage sealing rings, and a gap of 1 mm to 2.5 mm between the piston and the cylinder block, the first-stage sealing ring can filter the abrasive grains of the two-phase flow, and the second-stage sealing ring seals a pure liquid phase such as an aqueous liquid phase, thereby realizing good sealing performance for the finishing medium. Also, the inventor has discovered that within the range of a gap of 1 mm to 2.5 mm, it is possible to ensure that the piston can move smoothly along the wall surface of the cylinder block 18 to push and discharge the finishing medium 18 while maintaining a good sealing effect.

[0075] Next, referring to what is shown in FIG. 3, in the piston 21, the first concave groove 211 is formed as a separate component. The upper surface 212 of the main body of the piston 21 is a flat surface, and a cover plate 20 is detachably provided thereon. The cover plate 20 has an inclined surface 201 on its outer periphery. The inclined surface 201 and the upper surface of the piston 21 form a single-sided inclined groove to constitute the first concave groove 211. The second concave groove 210 is provided on the side wall of the piston. The material of the first seal ring 17 is a hard polymer material, and the material of the second seal ring 170 is a soft polymer material. The principle will be described. The inventor discovered that due to the high pressure, no matter how the first seal ring seals, the abrasive grains will be inserted into the gap between the cylinder wall and the seal ring, damaging the seal ring. Therefore, a single-sided inclined groove and a hard seal ring structure are provided to guide the abrasive grains to automatically insert / slide into the first seal ring 17 to form an inserted self-sealing structure. For this reason, the first seal ring 17 is made of a hard polymer material. Also, after most of the abrasive grains have automatically inserted into the first seal ring 17, what should be sealed by the second seal ring 170 is the liquid phase in the two-phase flow. Therefore, the soft second seal ring 170 is used for sealing. The reason why the first concave groove 211 should be formed as a separate component will be described. That is, the inventor discovered that the first seal ring 17 adopts a hard polymer structure and is subject to a large pressure. If a concave groove is directly provided on the side wall of the piston, the first seal ring 17 cannot be fixed. Therefore, the first concave groove 211 is formed as a separate component. During assembly, after the first seal ring is placed on the upper surface 212 of the main body of the piston 21, the cover plate 20 is put on and tightened by bolts 7. In some embodiments, the inclination angle of the single-sided inclined groove, that is, the inclined surface 201, is made greater than 60° to provide sufficient tightening force.

[0076] In some embodiments, as the specific materials of the first seal ring 17 and the second seal ring 170, the polymer material of the first seal ring may satisfy that the flexural modulus is 1.9 GPa to 3.6 GPa, the elongation rate is 60% to 120%, and the Knoop hardness is 90 HK to 100 HK. Thereby, the first seal ring 17 should have a certain rigidity, be difficult to generate obvious distortion, and also have good surface self-lubricity, low pressing shrinkage, and the abrasive grains can be well embedded in the material, and after the abrasive grains are embedded, it should be easy to slide in the material subsequently. The polymer material of the second seal ring 170 satisfies that the flexural modulus is 0.2 GPa to 0.25 GPa, the elongation rate is 300% to 380%, and the flexural strength is 80 to 100 MPa. Thereby, the second seal ring 170 should have good elasticity, be able to generate obvious distortion, and also be able to exert the sealing ability for aqueous substances due to the significant pressing shrinkage length and have high flexural strength. Otherwise, it is easy to break after moving and bending.

[0077] In some embodiments, the material of the first seal ring 17 may be one of pp, polytetrafluoroethylene, nylon, and peek, and the material of the second seal ring 170 may be one of silica gel, rubber, and butyronitrile. The above materials are easy to obtain and have low costs.

[0078] Next, referring to what is shown in FIG. 3, the second concave groove 211 may include at least two concave grooves, namely a first sub-concave groove 2111 and a second sub-concave groove 2112, in the direction from the topmost part to the bottommost part. Among them, the ratio of the depth of the second sub-concave groove 2112 to the depth of the first sub-concave groove 2111 is 1.2 to 1.5. And a third sub-concave groove 2113 may be further provided in the direction of the bottom of the second sub-concave groove 2112, and more sub-concave grooves may be further provided. The ratio of the depth of the second sub-concave groove 2112 to the depth of the third sub-concave groove 2113 is 1.2 to 1.5. The second seal rings 170 arranged corresponding to the first sub-concave groove 2111, the second sub-concave groove 2112, and the third sub-concave groove 2113 are the seal rings 16, 15, and 14 respectively, and their functions are all to seal water. The shape of the concave groove may adopt a trapezoidal groove that facilitates processing and fixing of the seal ring. The depth of the second sub-concave groove 2112 is larger than that of the first sub-concave groove 2111 and the third sub-concave groove 2113 adjacent to it, and its beneficial effects are as follows. That is, it can reliably seal the finishing medium in multiple stages with respect to the fluid phase, realizing preliminary sealing by the first sub-concave groove 2111, complete sealing by the second sub-concave groove 2112, and guarantee sealing by the third sub-concave groove 2113.

[0079] Next, referring to what is shown in Fig. 3, in some embodiments, the cylinder wall of the cylinder block 18 has a coating, the thickness of the coating is 50 μm to 220 μm, the hardness is 1500 HV to 2200 HV, and the material is one kind or a combination of oxide, carbide, boride and nitride ceramics. Its beneficial effect is to surely ensure the sealing effect. The principle will be described. The inventor found that during the operation of the device, in the process where the two-phase flow of the fluid phase and the abrasive solid phase moves at high speed, the abrasive grains are sandwiched between the clearance of the seal ring and the cylinder block, rub against the cylinder wall, and when abrasion marks are generated on the cylinder wall due to friction, it will cause a complete failure of the sealing system and leakage of the fluid phase. Therefore, it is necessary to harden the cylinder wall. The process for realizing the coating introduced above may solve the wear resistance problem of the cylinder wall by spraying a special WC coating on the inner cavity of the cylinder block. The specific components of the WC coating sprayed on the cylinder block are as follows. That is, the particle size of the WC powder is 15 to 100 μm, the content of the WC powder is more than 85%, the content of the molybdenum powder is 1% to 4%, the content of the silicon powder is 1% to 5%, and the content of the boron powder is 1 to 5%. After spraying and sintering, a molybdenum-silicon-boron alloy phase is formed in the WC coating. The molybdenum-silicon-boron alloy has a low friction coefficient and is mixed in the WC coating to increase the strength and hardness of the WC coating as a strengthening phase. When spraying, the particle temperature is lower than 1500 °C. At a low temperature, the thermal deformation amount of the cylinder block after receiving heat is reduced, ensuring the accuracy of the final size of the cylinder block. The spraying distance is 10 mm to 50 mm. With a small spraying distance, the bonding force of the coating is ensured to be greater than 100 MPa. In some embodiments, the surface roughness Ra of the coating is 0.05 μm to 0.4 μm, the roundness of the cylinder block is 100 μm or less, the cylindricity is 200 μm or less, and the diameter of the cylinder block is 100 mm to 400 mm. Thereby, the relative movement between the piston and the cylinder block generates a rolling force, preventing damage and peeling of the coating, and further ensuring the service life of the sealing system and the certainty of the sealing effect.To achieve this effect, the process may involve surface honing the coating. The honing tool should be made of zirconium oxide ceramic, and the honing speed should be less than 80 r / min. The low speed ensures that the coating will not peel, crack, or fall off during honing.

[0080] Continuing with reference to what is shown in FIG. 2, the finishing device 10 may further include a diagnostic device. The diagnostic device has a flow velocity sensor and / or a flow rate sensor and a pressure sensor to diagnose the state of the finishing process by detecting the flow velocity and / or flow rate and pressure of the finishing medium. The sensors may be arranged at a distance close to the upstream end of the workpiece 34. To explain the principle, the inventor found that when the finishing process proceeds normally, the flow velocity / flow rate / pressure of the finishing medium at the upstream end of the fine internal flow path is only affected by the shape of the internal flow path and the quality of the surface of the internal flow path. The flow resistance and flow rate of the internal flow path itself generate a reaction force that directly acts on the flow velocity / flow rate / pressure at the upstream end. Since the downstream end of the internal flow path is larger than the cross-sectional area of the internal flow path, after the finishing medium flows out of the internal flow path, it is in a state of freely flowing "unloaded" with respect to the downstream end, and the downstream end of the internal flow path does not affect the flow velocity / flow rate / pressure at the upstream end. Therefore, by only measuring the change in the inlet velocity at the upstream end, the processing quality of the internal flow path can be reflected.

[0081] The pressure sensor includes the following. That is, a highly sensitive piezoelectric quartz sensor 28 and a high-resolution multi-channel data acquisition device 27 are adopted to monitor the data of the pressure gauges 29 at multiple ports in real time, completely record the quasi-static and highly dynamic pressure processes in the finishing process, thereby obtaining accurate flow resistance data in each flow path and ensuring the optimal finishing effect. The flow velocity and / or flow rate sensor includes a flow velocity flow meter 24, a flow velocity flow rate piezoelectric sensor 25, and a flow velocity flow rate data acquisition device 26. It adopts the ultrasonic measurement principle, and the flow velocities and flow rates at multiple ports are synchronized by an ultrasonic flow meter based on the Doppler method principle. Ultrasonic measurement is non-contact, which can completely avoid damage to the flow velocity flow meter caused by two-phase flow, greatly improve the response sensitivity of the entire system, and obtain the optimal finishing time.

[0082] Although the present invention has been disclosed in the embodiments as described above, it is not intended to limit the present invention by the embodiments. Those skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any content that does not deviate from the technical solution of the present invention and any amendments, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention fall within the protection scope defined in the claims of the present invention.

Claims

1. A thrust system, A piston, and a closed system comprising a cylinder block for accommodating a finishing medium that fits onto the piston and performs finishing. The thrust system is communicated with one end of the piston, and provides a driving force to the closed system to push the finishing medium and discharge it from the outlet end of the cylinder block. A closed system, A transport pipeline system for transporting the finishing medium accommodated in the corresponding closed system to the port of the internal flow path work where the finishing is to be performed. The upstream end is connected to the outlet end of the closed system, and the downstream end is a transport pipeline system for discharging the finishing medium to perform finishing on the internal flow path work. A recovery system comprising a recovery container, a recovery pipeline, a reflux pipeline, a power assembly, and a control valve assembly. The control valve assembly includes a first valve and a second valve. The recovery container is communicated with the work through the recovery pipeline and with the closed system through the reflux pipeline. The first valve is adapted to the closed system and a low-pressure environment. The second valve is located in the reflux pipeline and is adapted to the reflux container and the closed system. The power assembly is communicated with the recovery container and can provide power to the recovery container so that the finishing medium in the recovery system can reflux to the cylinder block. A recovery system, The piston has at least a first concave groove and a second concave groove from the top to the bottom. The closed system further comprises a sealing ring located between the piston and the cylinder block, including a first sealing ring provided in the first concave groove and a second sealing ring provided in the second concave groove. The clearance between the piston and the cylinder block in the radial direction is 1 mm to 2.5 mm. The first concave groove is composed of a separate part. The upper surface of the piston is flat, and a cover plate is detachably provided thereon. The cover plate has a slope on the outer periphery, and the slope and the upper surface of the piston form a single-side inclined groove to constitute the first concave groove. The second concave groove is provided on the side wall of the piston. The material of the first sealing ring is a hard material, and the material of the second sealing ring is a soft material. A finishing device characterized by this.

2. The first valve is a nozzle flapper valve. The finishing device has a first state and a second state, among which, In the first state, the finishing medium is transported from the closed system to the transport pipeline system. The finishing medium accommodated in the closed system acts on the nozzle of the nozzle flapper valve so as to close the nozzle flapper valve, and the second valve is closed. In the second state, the nozzle flapper valve is opened, and the transport of the finishing medium from the closed system to the transport pipeline system is stopped so as to communicate the closed system with the external low-pressure environment. The action of the finishing medium accommodated in the closed system on the nozzle of the nozzle flapper valve is stopped, and the second valve is opened. The power assembly applies pressure to the recovery container until a first pressure is reached. Accordingly, there is a pressure difference between the recovery container and the closed system, between the first pressure and the external low-pressure environment. The finishing device according to claim 1, characterized in that.

3. The second valve is a solenoid valve, and the control valve assembly further includes a sensor for detecting the mass of the finishing medium in the recovery container. The solenoid valve is opened or closed according to the result of the mass detected by the sensor. The finishing device according to claim 2, characterized in that.

4. The sensor is a gravity sensor, and the height of the recovery container is higher than the height of the closed system. The finishing device according to claim 3, characterized in that.

5. The recovery container is a transparent container, and the finishing medium accommodated therein is visible from the outside. The finishing device according to claim 1, characterized in that.

6. The container wall of the recovery container has a volume scale line. The finishing device according to claim 5, characterized in that.

7. A thermometer or a viscometer is provided in the recovery container. The finishing device according to claim 1, characterized in that.

8. Further comprising a diagnostic device, the diagnostic device having a flow velocity and / or flow rate sensor and a pressure sensor for detecting the flow velocity and / or flow rate and pressure of the finishing medium. The finishing device according to claim 1, characterized in that.

9. The material of the first seal ring satisfies that the flexural modulus is 1.9 GPa to 3.6 GPa, the elongation rate is 60% to 120%, and the Knoop hardness is 90 HK to 100 HK. The material of the second seal ring satisfies that the flexural modulus is 0.2 GPa to 0.25 GPa, the elongation rate is 300% to 380%, and the flexural strength is 80 MPa to 100 MPa. The finishing device according to claim 1 is characterized in that.

10. The finishing medium includes a liquid phase and a solid phase. The viscosity of the liquid phase is less than 1000 cP. The solid phase includes abrasive grains. The workpiece to be finished is a fine internal flow path workpiece with a diameter of 3 mm or less and a ratio of length to diameter of 50:1 or more. The finishing device according to claim 1 is characterized in that.

11. The finishing device according to any one of claims 1 to 10 is adopted. The finishing medium includes a liquid phase and a solid phase. The viscosity of the liquid phase is less than 1000 cP. The solid phase includes abrasive grains. The workpiece to be finished is a fine internal flow path workpiece. The diameter of the fine internal flow path is 3 mm or less and the ratio of length to diameter is 50:1 or more. The thrust system of the finishing device applies a predetermined pressure to the finishing medium so that the finishing medium flows in the fine internal flow path at a flow rate greater than 5 m / s. The flow rate of the finishing medium flowing into the fine internal flow path from one end thereof reaches the saturation value of the flow rate that can be accommodated by the diameter of the fine internal flow path. Thus, the hydraulic pressure inside the internal flow path is in a state where pressure accumulates. A method for finishing an internal flow path workpiece is characterized in that.

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