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 passages, and more particularly to a finishing device and a finishing method. [Background technology]

[0002] Components with fine and complex internal flow path structures are widely used in industrial fields such as aerospace, ships, nuclear, automobiles, and molds. In particular, components related to fluid power systems often have complex internal bore structures such as fine flow paths, small-diameter deep holes, and connections between fine flow paths and small-diameter deep holes, and perform functions such as transporting, exchanging, or applying hydraulic pressure to fluids, such as fuel nozzles, heat exchangers, hydraulic modules, and oil passage control throttles in various engines for aerospace, ships, and automobiles.

[0003] Process technologies capable of fabricating fine and complex internal flow channels include precision machining, femtosecond / water jet guided / long pulse laser processing, spark machining, and additive manufacturing (3D printing), etc. Except for additive manufacturing technology, the fine and complex internal flow channel structures fabricated by other single processes are relatively simple and have a small length-to-diameter ratio, so they need to be combined with other combined processes such as welding to fabricate fine and complex internal flow channels. Precision machining can produce fine, complex internal flow passages with problems such as burrs, sharp corners, and uneven joints. Femtosecond laser machining can produce adhered residual particles and a "step" effect on the surface of internal flow passages. Guided water jet / long-pulse laser and spark machining can produce a remelted layer on the surface of internal flow passages. Additive manufacturing (3D printing) is a technology that separates complex 3D structured part models into 2D structures and then layers them together to form them. It enables the integrated molding of complex, fine, and intricate internal flow passage parts, and is therefore increasingly being applied in industrial fields such as aerospace, automotive, and molds. However, additive manufacturing technology has its own process characteristics, such as temperature gradients and layer-by-layer molding, which can cause semi-sintered or adhered powder particles and a "step" effect on the surface of the internal flow passages of parts.

[0004] Burrs during machining, particles sintered into internal flow passages during femtosecond laser processing, and adhesive powder on the surface of internal flow passages during additive manufacturing affect the performance and safety of components. When burrs, attached residual particles, or adhesive powder fall off due to high-speed friction between the fluid flowing into the internal flow passage and the surface, they become redundant and spread with the fluid, block the oil passage, or cause mechanical wear failure, resulting in serious safety hazards. Highly rough inner surfaces are prone to fatigue cracks during long-term use, and carbon accumulation is also likely to occur in high-temperature oil passage systems. Cutting edge marks on the flow passage surface during machining, sharp corners or steps at machined joints, and "step" phenomena on the surface of internal flow passages during femtosecond laser and additive manufacturing processes can cause turbulence, vortices, and a sudden increase in fluid frictional drag during fluid movement, leading to fluid runaway and vibration, shortening the service life of components. Rough surfaces can generate a large number of cavitation bubbles in the fluid, affecting combustion and hydraulic power, and can also cause cavitation corrosion. For internal flow channels and small connecting holes in parts made of specific materials, such as hollow blades, microcracks are likely to occur on the surface of the remelted layer, leading to early failure of the part. Therefore, it is necessary to reduce the thickness of the remelted layer or to prevent its appearance.

[0005] Therefore, when processing the internal flow passage surfaces of fluid power components using technologies such as precision machining, femtosecond / water jet guided / long pulse laser machining, spark machining, and additive manufacturing (3D printing), adverse issues such as burrs, adhesive powder, sintered particle residues, rough surfaces, and remelted layers can occur. Appropriate surface finishing techniques must be used to remove these adverse effects and meet the performance requirements of the product.

[0006] However, currently, there is no technology that can effectively finish the surfaces of fine and complex internal flow passages. Therefore, the roughness of the inner surface of fine and complex internal flow passage workpieces made by additive manufacturing generally only has an initial average roughness Ra of 6.3 μm or more after additive manufacturing. There are no products with an optimal surface roughness Ra of 1.6 μm or less for internal flow passages, and there are no products with an optimal surface roughness Ra of 0.8 μm or less for fine and complex internal flow passage workpieces made by laser processing or spark processing. In addition, with regard to machined workpieces with fine and complex internal flow paths, there are no products with an optimal surface roughness Ra of 0.4 μm or less for the internal flow paths. However, currently, when fine and complex internal flow paths have complex, irregularly shaped flow paths such as S-shaped, L-shaped, U-shaped, or O-shaped bends, this cannot be achieved with machining, which only allows for linear feed, and can only be achieved with methods such as additive manufacturing. Therefore, at present, there are no products with an optimal surface roughness Ra of 1.6 μm or less for fine, irregular, and complex internal flow paths produced by additive manufacturing. Summary of the Invention

[0007] SUMMARY OF THE INVENTION It is an object of the present application to provide a finishing apparatus and a finishing method.

[0008] In a first aspect, the present application provides a finishing device, the finishing device comprising: a thrust system; a sealed system including a piston; a cylinder block fitted to the piston and containing a finishing medium for performing finishing processing; the thrust system being connected to one end of the piston and providing a driving force to the sealed system to push the finishing medium to be discharged from an outlet end of the cylinder block; and a transport pipeline system for transporting the finishing medium contained in the corresponding sealed system to a port of an internal flow path workpiece to be finished; the transport pipeline system having an upstream end connected to the outlet end of the sealed system and a downstream end for discharging the finishing medium to perform finishing on the internal flow path workpiece. The recovery system includes a pipeline system, a recovery container, a recovery line, a return line, a power assembly, and a control valve assembly, wherein the control valve assembly includes a first valve and a second valve, the recovery container is connected to the workpiece via the recovery line and to the sealed system via the return line, the first valve is connected to the sealed system and a low-pressure environment, and the second valve is located on the return line and is connected to the return container and the sealed system, the power assembly is connected to the recovery container and can provide power to the recovery container, and the recovery system quickly returns the finishing medium in the recovery system to the cylinder block.

[0009] In the technical solution of the embodiment of the present application, the recovery system adopts the first valve, the second valve, and the synergistic effects of the first valve, the second valve, the sealed system, the recovery container, the return pipeline, and the power assembly, thereby ensuring that the return flow of the sealed system and the discharge flow of the finishing medium transported from the sealed system do not interfere with each other, and the finishing medium contained in the recovery system can be quickly returned to the sealed 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, in which in the first state, finishing medium is transported from the sealing system to the transport pipeline system, the finishing medium contained in the sealing system acts on a nozzle of the nozzle flapper valve to close the nozzle flapper valve, and the second valve is closed; in the second state, transportation of finishing medium from the sealing system to the transport pipeline system is stopped, the finishing medium contained in the sealing system stops acting on the nozzle of the nozzle flapper valve to open the nozzle flapper valve and connect the sealing system to the external low-pressure environment, and the second valve is opened; and the power assembly applies pressure to the collection container up to a first pressure, thereby creating a pressure differential between the collection container and the sealing system 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 comprises a sensor for detecting the mass of finishing medium in the collection vessel, and the solenoid valve is opened or closed as a result of the mass detected by the sensor.

[0012] In some embodiments, the sensor is a gravity sensor and the height of the collection container is greater than the height of the sealing system.

[0013] In some embodiments, the collection container is a transparent container, allowing the finishing medium contained therein to be viewed from the outside.

[0014] In some embodiments, the container wall of the collection container has volume graduations.

[0015] In some embodiments, the collection vessel is equipped with a thermometer or a viscometer.

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

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

[0018] In some embodiments, the first groove is a separate piece, the upper surface of the piston is flat, a cover plate is detachably mounted thereon, the cover plate has a slope on its outer periphery, and the slope and the upper surface of the piston form a single-sided inclined groove to form the first groove, the second groove is provided in a side wall of the piston, the first seal ring is made of a hard material, and the second seal ring is made of a soft material.

[0019] In some embodiments, the material of the first seal ring satisfies the following: a flexural modulus of 1.9 GPa to 3.6 GPa, an elongation of 60% to 120%, and a Knoop hardness of 90 HK to 100 HK; and the material of the second seal ring satisfies the following: a flexural modulus of 0.2 GPa to 0.25 GPa, an elongation of 300% to 380%, and a flexural strength of 80 MPa to 100 MPa.

[0020] In some embodiments, the finishing medium comprises a liquid phase and a solid phase, the viscosity of the liquid phase being less than 1000 cP, the solid phase comprising abrasive grains, and the workpiece being finished is a fine internal channel 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, which employs the finishing apparatus described in the first aspect, wherein the finishing medium comprises a liquid phase and a solid phase, the viscosity of the liquid phase being less than 1000 cP, and the solid phase comprising abrasive grains, the workpiece to be finished is a fine internal passage workpiece with a diameter of 3 mm or less and a length-to-diameter ratio of 50:1 or more, the thrust system of the finishing apparatus applies a predetermined pressure to the finishing medium so that the finishing medium flows through the fine internal passage at a flow velocity greater than 5 m / s, and the flow rate of the finishing medium flowing into the fine internal passage from one end thereof reaches a saturation value of the flow rate that can be accommodated by the diameter of the fine internal passage, thereby causing the hydraulic pressure inside the internal passage to be in a pressure-filled state. [Brief explanation 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 conjunction with the accompanying drawings and embodiments, which should be noted that the accompanying drawings are illustrative only and are not drawn to scale, and should not be considered as limiting the scope of protection actually claimed by the present invention.

[0023] [Figure 1] 1 is a conceptual flow chart of a finishing method according to some embodiments of the present application; [Figure 2] 1 is a schematic diagram of a finishing device according to some embodiments of the present application; [Figure 3] Enlarged view of part A in Figure 2 [Figure 4] Enlarged view of part B in Figure 2 DETAILED DESCRIPTION OF THE INVENTION

[0024] Various embodiments or examples of implementing the above-mentioned technical proposal are disclosed below. To simplify the disclosure, specific examples of each element and arrangement are described below, but these are merely examples and do not limit the scope of protection of the present invention. The terms "one embodiment," "one embodiment," and / or "several embodiments" refer to features, structures, or special features associated with at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "alternative embodiments" mentioned more than once in different places in this specification do not necessarily refer to the same embodiment. Furthermore, some features, structures, or special features in expressions such as "several embodiments," "other embodiments," and "still other embodiments" of the present application may be appropriately combined.

[0025] Flowcharts are used herein to explain the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in precise order. Other operations may be added to these processes, or certain step or step operations may be removed from these processes.

[0026] Furthermore, the average roughness described below refers to the case where multiple areas on the surface to be measured are selected, measured, and the average value is taken to obtain the average roughness of the measured surface. The optimum roughness described below refers to the case where multiple areas on the surface to be measured are selected, measured, and the minimum value is taken to obtain the optimum roughness of the measured surface. For example, when performing roughness measurement, the area to be roughened is a pipe segment with a length of 8 mm, and multiple 8 mm pipe segments are selected and measured in the pipe to be measured, and the minimum value can be obtained.

[0027] Components with intricate and detailed internal flow passage structures are widely used in industries such as aerospace, marine, nuclear, automotive, and mold manufacturing. However, current machining processes, such as precision machining, femtosecond / waterjet guided / long-pulse laser machining, spark machining, and additive manufacturing (3D printing), can result in undesirable problems such as burrs, adhesive powder, sintered particle residues, rough surfaces, and remelted layers. Appropriate surface finishing techniques are required to eliminate these undesirable effects and ensure the product meets its performance requirements.

[0028] Currently, there are no products with an optimum surface roughness Ra of 1.6 μm or less for fine internal flow passage workpieces made by additive manufacturing, no products with an optimum surface roughness Ra of 0.8 μm or less for fine internal flow passage workpieces made by laser processing or spark processing, and no products with an optimum surface roughness Ra of 0.4 μm or less for fine internal flow passage workpieces made by machining.However, if the fine internal flow passage has an irregular flow passage structure such as an S-shaped bend, L-shaped bend, U-shaped bend, or O-shaped bend, this cannot be achieved by linear feed machining and can only be achieved by additive manufacturing, and so there are currently no products with an optimum surface roughness Ra of 1.6 μm or less for fine internal flow passage workpieces made by additive manufacturing.

[0029] The inventors have conducted in-depth research and have tried and compared various finishing methods for various internal flow passage surfaces, and have found that when the internal flow passage of a part has a large diameter (>3mm), a small length-to-diameter ratio (<50:1), and extends in a substantially straight line, it can be finished using common methods such as manual polishing, chemical, electrochemical, plasma, magnetic force, magnetorheology, abrasive flow, water jet, and ultrasonic. However, when it comes to a fine internal flow passage with a small diameter (<3mm) and a large length-to-diameter ratio (>50:1), (1) Abrasive flow technology was employed, using a semi-solid ointment finishing medium with high rigidity to finish the inner cavity through a pressure grinding mechanism. However, the inventors discovered that this creep fluid, with its extremely low Reynolds number, makes it difficult to achieve uniform processing through complex, long-distance microchannels. It is prone to blockages at bends and dead corners, and forcing its passage through can cause the channel to deform or tear. Even if the fluid barely passes through an internal channel with a length-to-diameter ratio of 50:1 or more, the pressure and flow rate rapidly decrease with increasing fluid stroke, resulting in "excessive grinding" at the ports of the internal channel, while the pressure and flow rate loss is so great that the interior becomes "under-ground." Furthermore, the water-insoluble colloidal abrasive flow medium tends to remain in the curves and dead corners of the internal channel, making it difficult or impossible to completely remove after processing. (2) Abrasive water jet technology, also known as fine abrasive slurry jet, high-velocity flow, or high-velocity water particle finishing, is used. By applying hydraulic pressure to the water jet nozzle, a water jet containing abrasive particles is ejected from the nozzle, and the impact kinetic energy washes away the surface material of the workpiece. However, because the distance between the water jet nozzle and the part surface is short, abrasive water jet technology is not effective on fine internal flow passages with small internal flow passage diameters (less than 3 mm) and large length-to-diameter ratios (more than 50:1). (3) Magnetic finishing technology can only produce a light polish on the surface of internal flow passages larger than 3 mm and extending in a roughly linear fashion. It cannot produce an effective surface finish on intricate, three-dimensional internal flow passages less than 3 mm in diameter, such as S-, L-, U-, O-, or spiral bends. The reasons for this are as follows: Magnetic finishing is a flexible process that uses relatively large magnetic needle abrasive grains. It is based on the principle that convex and concave points on a surface are simultaneously processed under the action of an applied magnetic field. Therefore, these flexible processing methods can only produce a light polish on the surface. Even with a large amount of material removal, it cannot significantly improve the "step" effect on the surface, reduce surface roughness, significantly remove powder and particles adhering to the surface, or reduce burrs. Furthermore, because this method is limited by the movement of the magnetic field, it cannot be used to finish complex internal flow passages extending in three dimensions in parts. (4) Although the chemical finishing method was adopted, the small diameter of the internal flow passages meant that only a small amount of corrosive solution could be accommodated, making the efficiency of the chemical finishing method extremely low, and even preventing finishing due to local accumulation of reactive bubbles. (5) Electrochemical, plasma finishing, and ultrasonic methods have been adopted, but they are unable to finish fine and complex internal flow paths because it is difficult to place tracing electrodes within the narrow, three-dimensionally stretched flow paths, including S-shaped bends, L-shaped bends, U-shaped bends, O-shaped bends, and spiral bends.

[0030] Furthermore, with regard to (4) and (5), methods such as chemical, electrochemical, and plasma finishing can cause various corrosion and altered layer defects in the microstructure of the flow path substrate, and the corrosive liquid and reactive gases have adverse effects on the environment and equipment. At the same time, (4) and (5) are also flexible processing methods, and similarly have drawbacks to (3), in that they can only achieve a slight polishing improvement on the surface, and even if a large amount of material is removed, they cannot significantly improve the surface "step" effect, reduce surface roughness, or significantly remove powder, particles, and burrs adhering to the surface.

[0031] Based on the above, the inventor has conducted extensive research and discovered that the above-mentioned processing method is not suitable for finishing fine internal flow paths because it is difficult to finish the deep parts of the fine internal flow paths and / or the finishing quality is not ideal for the structure of the fine internal flow paths.

[0032] Based on the above, the inventor further researched and invented a surface finishing method for fine internal passages. This method uses a two-phase liquid finishing medium with a viscosity of less than 1000 cP, and the flow rate of the two-phase finishing medium within the fine internal passage is set to be greater than 5 m / s. The flow rate at one end of the fine internal passage is set to the saturation value that the diameter of the fine internal passage can accommodate. This creates a pressure-blocking state within the internal passage, creating a means for the liquid to reach a saturation flow rate within the fine internal passage. In other words, the synergistic effects of the low-viscosity liquid phase, the fluid flow rate of the finishing medium, and the saturation flow rate have solved the difficult problem of finishing fine internal passages. The principle behind this method is as follows. First, the synergistic effects of the low-viscosity liquid phase, fluid flow rate, and saturation flow rate allow the finishing medium to smoothly penetrate into the microscopic, complex internal channels and form a non-Newtonian-like state within the channels. The fluid boundary layer is parallel to the channel surface, and the abrasive grains in the "knife-like" hard non-Newtonian fluid achieve target machining of surface convexities through shear friction. Furthermore, the synergistic effects of these three factors create a micro-cutting force between the abrasive grains in the finishing medium and the surface of the microscopic, complex internal channels. This allows the optimal surface roughness to match the average contact length of the abrasive grain cutting edge, regardless of the material of the microscopic, complex internal channel. This enables the optimal surface roughness to be achieved within the range of the optimal surface roughness Ra of 0.05 μm, even achieving ultra-mirror quality, surpassing the limitations of abrasive flow and waterjet technologies. The cutting mechanism of abrasive flow technology relies on volume forces generated by the abrasive grains pressing against the surface, making it prone to pitting (Ra > 0.8 μm) when machining low-hardness metals and flexible polymer materials. The cutting force in abrasive waterjet technology is the erosion force caused by the impact of abrasive grains on the surface, and when machining soft metals, the surface is prone to roughening (Ra>0.8μm).

[0033] In order to develop a finishing device corresponding to the above surface finishing method, the inventors have found that the finishing device needs to adopt a sealed system for containing a finishing medium for performing the finishing process, and a transport pipeline system for transporting the finishing medium contained in the corresponding sealed system to a port of the internal flow path workpiece where the finishing is to be performed.

[0034] Some finishing devices may employ multiple sealed systems interconnected by the workpiece to realize fluid exchange. For example, two sealed systems and two transport pipeline systems may be used, each transport pipeline system transporting the finishing medium contained in the corresponding sealed system to a different port of the internal flow path workpiece where finishing is performed. That is, one sealed system discharges the finishing medium to the workpiece, and the other sealed system receives the finishing medium flowing out of the workpiece. When the finishing medium in one sealed system is used up, the other sealed system can continue finishing the workpiece in the opposite direction using the received finishing medium. That is, at this time, the other sealed system discharges the finishing medium to the workpiece, while the sealed system whose finishing medium is used up again receives the finishing medium flowing out of the workpiece. This ensures that the finishing medium contained in at least one sealed system is always available for the workpiece, ensuring continuous and uninterrupted finishing of the workpiece, thereby realizing an efficient finishing process.

[0035] However, the inventor has further researched and found that for some workpieces with fine internal flow passages, the above-mentioned two-way machining method cannot be adopted, and therefore the finishing device with multiple sealing systems cannot be applied. For example, for workpieces with fine internal flow passages, the following configurations exist: 1) Of the two ports of a fine internal flow passage, only one port can achieve a high-strength sealed connection, while the other port cannot achieve a high-strength sealed connection, for example, because the port has an irregular shape or a thin-walled configuration, and the corresponding sealed joint cannot be machined, or does not have the strength to withstand a high-strength sealed connection. 2) The minute internal flow passages have a specific throttle and guide function, like a Tesla valve, which allows fluid to flow only in one direction, and in the other direction, the fluid can only flow slowly or not at all. 3) The fine internal flow passages are connected to a group of densely packed holes, such as the film cooling holes in a single crystal blade of an aircraft engine, with one end being the bore port of the single crystal blade and the other end consisting of densely packed small holes in a different irregular zone in the blade body.

[0036] In the above configuration, the two-phase flow of the finishing medium can only be fed into one designated port of the internal flow path and discharged from another port, and cannot flow in the opposite direction. That is, it is not possible to use multiple closed systems that are interconnected by the workpiece to achieve fluid exchange, such as a solution in which two closed systems are used to perform bidirectional processing on the workpiece.

[0037] Furthermore, after further research into the one-way processing method, it was discovered that because the flow rate of the finishing medium is fast, the rate at which the finishing medium is consumed by the closed system during the finishing process is high, and therefore it is necessary to quickly automatically return and replenish the finishing medium to the closed system.

[0038] In view of the above circumstances, the inventor conducted in-depth research and established a recovery system that utilizes the first valve, the second valve, and the synergistic effects of the two with the sealed system, recovery container, return pipeline, and power assembly, thereby ensuring that the return flow of the sealed system and the discharge flow of the finishing medium transported from the sealed system do not interfere with each other, and allowing the finishing medium contained in the recovery system to be quickly returned 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] It is understood that the internal flow channel surface finishing device disclosed in the examples of the present application contributes to solving the problem of being unable to efficiently process fine internal flow channel workpieces that have small internal flow channel diameters (3 mm or less), large length-to-diameter ratios (50:1 or more), and can only be processed by one-way flow of the finishing medium, by realizing high-speed replenishment of the finishing medium. However, it is understood that the disclosure of the examples of the present application can be applied not only to the surface finishing method and fine internal flow channel workpieces that can only be processed in one direction, but also to other fluid processing methods and internal flow channel workpieces.

[0040] It is important to clarify that the terms "diameter" and "length" in this context refer to 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 passage may be a circle, an ellipse, or the like, whose cross-sectional contour is formed by a closed curve (non-broken line). The cross-sectional shape of the internal flow passage may be a rectangle, a triangle, or the like, whose cross-sectional contour is formed by a closed broken line. Since the cross-sectional contour is formed by any closed curve (non-broken line) or a closed broken line, and the cross-sectional contour is an irregular shape, an equivalent diameter is introduced and defined as follows: For any cross-sectional shape, an ideal circle is taken to be equal to the actual cross-sectional area of ​​the cross-sectional shape, and the diameter of this ideal circle is the equivalent diameter. The equivalent length refers to the total distance that the fluid in the internal flow passage actually flows between the two ports of the internal flow passage.

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

[0042] Referring to FIG. 1 , the present application provides a method for surface finishing an internal flow passage, the method comprising: Using a liquid-solid two-phase flow finishing medium having a liquid phase viscosity of less than 1000 cP and a solid phase of abrasive grains; A predetermined pressure is applied to the finishing medium so that the finishing medium flows through the fine internal flow passage at a flow rate of greater than 5 m / s, the flow rate of the finishing medium flowing into the fine internal flow passage from one end thereof reaches the saturation value of the flow rate that can be accommodated by the diameter of the fine internal flow passage, and the liquid pressure inside the internal flow passage is in a pressure-trapping state.

[0043] The liquid herein has a viscosity of less than 1000 cP. All references to viscosity values ​​in this application refer to the Ubbelohde viscosity at room temperature (approximately 25°C). The optimal viscosity of the liquid phase for a finishing method for microscopic internal channels with different materials, dimensions, and initial average roughness can be achieved by continuously increasing the viscosity based on a lower limit. Currently, the lower limit of viscosity in the examples is approximately 50 cP. Through extensive testing, the inventors have found that for microscopic internal channels in common materials such as titanium alloys, high-temperature alloys, steel, ceramics, aluminum alloys, and polymeric materials, the viscosity of the liquid phase must be at least 50 cP to achieve the target roughness after finishing. The critical value of 1000 cP is not generally an optimal value, but rather the limit at which the finishing medium can flow continuously, smoothly, and stably through the microscopic internal channels.

[0044] The liquid phase described in the examples is, for example, an aqueous liquid phase, in which a certain thickener is added to deionized water so that the aqueous liquid has a certain viscosity. Benefits of using an aqueous liquid include low cost, easy availability, environmental friendliness, and ease of cleaning of the finishing medium after finishing is completed. However, it is understood that the liquid phase here is not limited to an aqueous liquid as long as it has a viscosity μ of less than 1000 cP.

[0045] The material of the solid-phase abrasive grains may be a common abrasive 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., or natural minerals including diamond / sand, mica, quartz, olivine, etc. Preferably, the abrasive grains may be a combination of one or more of diamond / sand and oxide ceramics.

[0046] When selecting the grain size and mass concentration of abrasive grains, it is common to gradually increase them based on the lower limit to obtain an optimal range. If the grain size and mass concentration are below the lower limit, the expected finishing effect will not be achieved; that is, the fine internal flow passages will not achieve the target surface roughness. The principle is that if the grain size is too small, the mass of the abrasive grains themselves will be too low to generate enough kinetic energy to achieve effective polishing; if the mass concentration is too low, the probability of grinding the surface processing point will be reduced, making effective polishing impossible. The selection of the lower limit is generally conservative; for example, any lower limit can be selected conservatively, provided that it does not exceed the upper limit of the grain size. The lower limit for the ratio of the internal flow passage diameter to the abrasive grain size is usually 20. That is, the diameter of the internal flow passage must ensure that at least 20 abrasive grains can pass through in parallel without clogging. That is, the upper limit of the abrasive grain size is usually 1 / 20 of the internal flow passage diameter, and the lower limit of the abrasive grain size is generally 1 / 5 of the upper limit. The lower limit of the abrasive mass concentration is generally 10 g / L, and the selection of the lower limit is generally relatively conservative because the system pressure is relatively high, and clogging of the abrasive may result in the scrapping of the workpiece and the system, or even tearing and explosion. Therefore, the abrasive particle size and mass concentration are gradually increased based on the specified lower limit until the abrasive particle size or mass concentration is too large, causing significant flow resistance and reducing the flow rate, and mutual collisions between abrasive particles affect the flow rate, reducing the flow rate and grinding effect. That is, the optimum value can be obtained by testing based on the lower limit.

[0047] A predetermined pressure is applied to the finishing medium so that the finishing medium flows through the fine internal passages at a flow rate greater than 5 m / s. The "predetermined pressure" here refers to a pressure that allows the finishing medium to flow through the fine internal passages at a flow rate greater than 5 m / s even at the initial stage of the finishing process. As the finishing process progresses, the surface roughness of the internal passages decreases, and under the same pressure conditions, the flow rate of the finishing medium within the fine internal passages becomes increasingly faster. It should be noted that the realized flow rate is within a certain range, so the "predetermined pressure" here is a concept of a range, rather than a specific value that can only be applied to the finishing medium. To measure the flow rate of the finishing medium within the fine internal passages, immersion measurement cannot be used, otherwise abrasive particles may damage the sensor probe. Ultrasonic velocity measurement can be used, or indirect measurement can be performed using the Hagen-Poiseuille law of viscous fluids (see equation below). In the formula, D is the internal flow passage diameter, l is the length of the fine internal flow passage, p is the pressure difference acting on both ends of the fine internal flow passage, i.e., 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, based on the theoretical critical conditions for forming non-Newtonian fluids and the critical value obtained by the inventors through long-term practice. According to engineering fluid mechanics data (e.g., Yang Shuren, Wang Zhiming, He Guangyu, et al., Engineering Fluid Mechanics [M]. Petroleum Industry Press, 2006), when pure water has a viscosity of 1 cP, the critical flow velocity of non-Newtonian fluids is greater than 16.6 m / s. However, the lower limit of the viscosity of the liquid phase in this embodiment is 50 cP, which is greater than 1 cP, so the critical flow velocity of non-Newtonian fluids is less than 16.6 m / s. At the same time, based on practical results, the inventors have found that ideal processing results cannot be achieved at a flow velocity less than 5 m / s, so the critical value is set to 5 m / s.

[0049] The flow rate of the finishing medium flowing into one end of the fine internal flow passage reaches a saturation value of the flow rate that can be accommodated by the diameter of the fine internal flow passage, and the liquid pressure inside the internal flow passage is in a pressure-filled state, i.e., a state of saturated flow rate as known in the art.

[0050] The saturated value of the flow rate and the saturated flow rate state here mean that when the fluid flows into the pipe, it fills the pipe cross section and the pipe cross section can accommodate the maximum number of fluid molecules in parallel.

[0051] It can be seen that the beneficial effects of the finishing method of the above embodiment are as follows:

[0052] The viscosity of the liquid phase of the finishing medium is less than 1000 cP, and the flow rate of the two-phase finishing medium within the fine internal passages is greater than 5 m / s, so that the flow rate at one end of the fine internal passages reaches the saturation value that the diameter of the fine internal passages can accommodate. This creates a pressure-blocking state within the internal passages, providing a means for the liquid to reach a saturation flow rate within the fine internal passages. In other words, the synergistic effects of the low-viscosity liquid phase, fluid flow rate, and saturation flow rate solve the difficult problem of finishing fine internal passages. The principle behind this is as follows. First, the synergistic effects of the low-viscosity liquid phase, fluid flow rate, and saturation flow rate allow the finishing medium to smoothly penetrate the microscopic internal channels, forming a non-Newtonian fluid state within the microscopic internal channels. The fluid boundary layer is parallel to the internal channel surface, and the abrasive grains in the "blade-like" hard liquid phase achieve targeted machining of convex surfaces through shear friction. This principle overcomes the problem of only slight polishing when simultaneously machining convex and concave surfaces during flexible machining. At the same time, the small cutting force generated by friction between the abrasive grains in the finishing medium and the microscopic internal channel surface allows for optimal surface roughness that matches the average contact length range of the abrasive cutting edge, regardless of the material of the microscopic internal channel. This breaks through the limitations of abrasive flow and waterjet technologies. The cutting mechanism of abrasive flow technology relies on volume forces generated by the abrasive grains pressing against the surface, which can easily result in pits (Ra > 0.8 μm) when machining low-hardness metals and flexible polymer materials. The cutting force in abrasive waterjet technology is the erosive force caused by the impact of abrasive particles on the surface. When machining soft metals, this can easily result in surface roughening (Ra > 0.8 μm). Furthermore, the low-viscosity, high-flow-rate, fluid-dynamic conformal machining method effectively polishes irregularities on the internal flow channel surface, such as steps, sharp corners, and geometric contour curvatures. This geometric streamlining of corners, sharp edges, internal flow channel contour curvatures, and hole shapes further improves the fluid dynamics of the internal flow channel. Furthermore, the above example proposed a critical flow velocity of 5 m / s for achieving a blade-like hard non-Newtonian fluid and target machining of convex surfaces through the shear friction of the abrasive particles.

[0053] Regarding the machining time of the finishing medium in the microscopic internal passage, the finishing medium may finish the microscopic internal passage during a reference period until the optimal surface roughness of the microscopic internal passage reaches a target value. The reference period may be a predetermined continuous period or a plurality of intermittent periods. The finishing process may automatically stop after a non-predetermined continuous period after starting, when it is detected that the flow rate of the finishing medium has reached a flow rate at which the optimal surface roughness of the microscopic internal passage reaches the target value. For example, as described above, in some embodiments, after starting machining, the optimal surface roughness is indirectly characterized by measuring the flow rate or flow rate of the finishing medium in the microscopic internal passage. When the flow rate or flow rate reaches a predetermined value, the corresponding optimal surface roughness reaches the target value, and the finishing process is stopped manually or automatically. The term "optimal surface roughness reaching the target value" here does not necessarily mean that the optimal surface roughness does not necessarily have to be measured directly, but may be characterized indirectly, such as by characterizing the flow rate or flow rate of the finishing medium within the microscopic internal passage, as described above. The above target values ​​refer to the set optimum surface roughness values, and generally refer to the requirements for the final optimum surface roughness of the fine internal flow passages, but it is not excluded that further finishing may be carried out after the above finishing step, and what is set at this time is not the requirement for the final optimum surface roughness.

[0054] In summary, the finishing method introduced in the above examples solves the long-standing industry challenge of finishing fine internal passages with diameters of 3 mm or less and length-to-diameter ratios of 50:1 or more by combining measures such as establishing a hydraulic system at both ends of the internal passage to be machined, utilizing a low-viscosity, high-speed solid-liquid two-phase fluid, achieving a saturation flow rate in the internal passage to be machined, and utilizing a fine cutting mechanism generated by the high-speed friction of abrasive grains in the two-phase flow against the surface of the internal passage.

[0055] 2 to 4 , in some embodiments, the present application provides a finishing apparatus 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 over the piston 21 and accommodates a finishing medium 8 for finishing. The thrust system 101 is connected to one end of the piston 21 and provides a driving force to the piston 21, forcing the finishing medium 8 to exit 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 passage workpiece 34 where finishing is performed. For example, the single sealing system 102 and transport pipeline system 103 shown in FIG. 2 correspond to the one-way processing port of the workpiece 34. The one-way processing port here refers to a predetermined port in the workpiece 34 to which the finishing medium is fed, as described above. 4, in some embodiments, the finishing apparatus may further include a tooling 31, which has at least two ports 310 corresponding to at least one inlet and at least one outlet of the workpiece 34. As can be seen from the above, during the finishing process, the finishing medium always flows in one direction, i.e., entering through the left port 310 and exiting through the right port 310. The left port 310, i.e., corresponding to the one-way processing port of the workpiece 34 described above, 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 line 36, a return line 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 connected to the workpiece 34 via the recovery line 36 and to the sealing system 102 via the return line 37. The first valve 38 is connected to the sealing system 102 and a low-pressure environment, where the low-pressure environment is defined relative to the high pressure provided by the power assembly 130. The low-pressure environment may be, for example, the open pressure of a room in which the finishing apparatus 100 is located. The second valve 39 is located in the return line 37 and is connected to the return container 35 and the sealing system 102. The power assembly 130 is connected to the recovery container 35 and can provide pressure to the recovery container 35.

[0057] The beneficial effects of the embodiment described above are as follows: By providing a recovery system that utilizes the first valve 38, the second valve 39, and the synergistic effects of the two with the sealing system 102, the recovery container 35, the return line 37, and the power assembly 130, it is possible to avoid interference between the return flow of the sealing system and the discharge flow of the finishing medium transported from the sealing system, and also to quickly return the finishing medium contained in the recovery system to the sealing system, thereby realizing high-speed replenishment of the finishing medium to the sealing system and ensuring the efficiency of the finishing process.

[0058] 2-4, in some embodiments, the specific configuration of the synergy between the first valve 38, the second valve 39, the sealing system 102, the collection container 35, the return line 37, and the power assembly 130 is as follows: the finishing device 100 has a first state and a second state, the first valve 38 is a nozzle flapper valve, and: In the first state, i.e., during the finishing process, the finishing medium is transported from the single sealed system 102 to the transport pipeline system 103 and to the one-way processing port of the workpiece 34. In the sealed system 102, the piston presses the stored finishing medium 8 with a large pressure, so that the first valve 38, located at the top of the cylinder block 18, is also pressed with a large pressure by the finishing medium 8. The nozzle of the first valve 38 is subjected to the pressure of the finishing medium 8, ejecting the finishing medium and pushing the flapper, thereby closing the nozzle flapper valve and closing the first valve 38. At this time, the second valve 39 is also closed. The finishing medium 8 flows from the sealed system 102 to the workpiece 34, and then from the workpiece 34 to the collection container 35 for storage.

[0059] In the second state, since the sealing system 102 can only accommodate a limited amount of finishing medium, after the piston has pushed out all of the finishing medium in the cylinder block, the transportation of the finishing medium from the sealing system to the transport pipeline system is stopped. At this time, the finishing medium contained in the sealing system stops acting on the nozzle of the first valve 38, so the nozzle of the first valve 38 does not discharge finishing medium, and the flapper in the nozzle flapper valve returns to a position that opens the first valve 38, and the sealing system 102 is connected to the external low-pressure environment. At this time, the second valve 39 is opened because the sensor detects the threshold mass in the collection container, and the collection container 35 and the sealing system 102 are directly connected via the return line 37. The power assembly 130 applies pressure to the collection container 35 until it reaches a first pressure, so that there is a pressure difference between the first pressure and the external low-pressure environment between the collection container 35 and the sealing system. Under the effect of this pressure difference, the finishing medium contained in the collection container 35 is quickly returned to the sealing system via the return line 37. The specific structure of the power assembly 130 can be, but is not limited to, an air compressor or air pump device 40 and a pressure line 41 to pressurize the collection container 35.

[0060] The use of a nozzle flapper valve to switch between the first and second states is highly effective. The principle behind this is as follows: The nozzle in a nozzle flapper valve can withstand high pressure and has sufficient strength, sealing, and jetting capabilities to withstand high-speed finishing media, effectively pushing the flapper, ensuring high sensitivity and reliability in switching the state of the nozzle flapper valve.

[0061] 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 collection container 35, and the second valve 39 is opened or closed based on the detection result from the sensor 42. For example, when the second state is reached and a 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 collection container 35 has exceeded a threshold value. This threshold value is typically 85% to 98% of the total mass of the finishing medium in the closed system. The reason for this will be explained below. That is, since there is a possibility that finishing medium may remain in the first valve 38, the transport pipeline system 103, and the sealing system 102, a certain amount of mass loss reserve space for the finishing medium is required. Furthermore, to prevent a backflow accident, which occurs when the second solenoid valve 39 is opened before all the finishing medium in the sealing system is expelled and the sealing system 102 transports the high-pressure finishing medium to the recovery system via the recovery pipeline 36, the threshold value should not be set too low. The specific value within the range of 85% to 98% varies depending on the mass of finishing medium remaining in the first valve 38, the transport pipeline system 103, and the sealing system 102, and can be obtained through field testing and adjustment. For example, a high threshold value, such as 98%, can be set. If the first valve 38 is opened but no reflux is observed, the threshold value can be correspondingly reduced to finally obtain the actual threshold value. Furthermore, after the threshold is reached, the control unit may typically delay by three seconds before commanding the second solenoid valve 39 to open. The three-second delay is required to prevent a backflow accident in which the second solenoid valve 39 is opened before all the finishing medium in the sealed system has been pushed out, causing the sealed system 102 to transport the high-pressure finishing medium to the recovery system via the recovery line 36. The sensitive and accurate control by the solenoid valve further ensures that the return flow of the sealed system and the discharge flow of the finishing medium transported from the sealed system do not interfere with each other.In some embodiments, the sensor 42 is a gravity sensor and the height of the collection container 35 is higher than the height of the sealing system 102, thereby making it possible to fully utilize the reliability of the detection results of the gravity sensor, and also because the collection container 35 is higher than the sealing system 102, the finishing medium 8 can be promoted to return under the action of gravity, further improving the efficiency of the return.

[0062] 2, in some embodiments, the collection container 35 is a transparent container, allowing the finishing media contained therein to be viewed from the outside. Specifically, the transparent material may be transparent glass, acrylic, or other materials. By using a transparent container that is visible from the outside as the collection container 35, an operator can directly observe characteristic information such as the amount of bubbles on the surface of the finishing media in the collection container 35, the color of the liquid phase, and the uniform dispersion state of the solid abrasive particles. This allows the operator to determine the ratio of the liquid phase to the gas bubble phase in the finishing media, and the color of the liquid phase to determine whether organic components such as thickeners have changed and are affecting the processing effect and whether environmental protection requirements are met. Furthermore, the finishing media 8 in the closed system 102 can determine whether the solid abrasive particles have aggregated or settled, thereby intuitively and effectively monitoring the status of the finishing media and the finishing process.

[0063] In some embodiments, the wall of the collection vessel 35 has volumetric graduations 43. This allows the volume of finishing medium entering the collection vessel 35 per unit time to be determined, as well as the flow rate of the finishing medium at the workpiece 34. By monitoring changes in the flow rate, it is possible to diagnose whether the finishing quality of the internal flow passages has reached the required flow rate and whether any speed fluctuations have occurred. The graduations also allow for more accurate determination of the volumetric amounts of the solid, liquid, and gas phases of the finishing medium.

[0064] It should be noted that the collection container 35 may be provided with a thermometer or viscometer to determine whether the temperature and viscosity of the finishing medium have changed significantly.

[0065] Because the collection container 35 is subject to low pressures under the operating conditions of the finishing apparatus 100 and is not typically subject to high pressures like the sealed system 102, the installation of the collection container 35 may also provide an intuitive means for the operator to monitor changes in the condition of the finishing medium and the finishing process.

[0066] In some embodiments, the length-to-diameter ratio of the transport pipeline system 103 is greater than 10:1, and the diameter of the outlet end is greater than 3 mm; the transport pipeline system 103 has multiple pipelines, and the cross-sectional area ratio of the upstream pipeline to the downstream pipeline of two adjacent pipelines is greater than 1.

[0067] The thrust system 101 includes a vertical plunger pump 5 connected to a piston 21 so that the piston 21 is movable relative to a cylinder block 18 along a vertical direction to provide driving force, and the multi-stage pipeline includes a first stage pipeline 22 and a second stage pipeline 23 connected adjacent to and downstream of the first stage pipeline, the first stage pipeline having a bend structure connected to an outlet end 190 of the cylinder block 18, and the bend structure is connected to the second stage pipeline 23 extending horizontally, thus realizing a combination of a vertical structure and a horizontal structure.

[0068] The thrust system 101 may be a hydraulic system, and as shown in FIG. 2, includes a motor 1, a hydraulic oil tank 2, a hydraulic pump 3, a pressure booster device 6, a vertical plunger pump 5, and an oil pipe 4. The motor 1 drives the hydraulic pump 2 to extract hydraulic oil at a constant pressure from the oil tank 2, and the pressurized oil is transported to the vertical plunger pump 5 after being boosted by the pressure booster device 6. The vertical plunger pump 5 is connected to the piston 21 via the ball head 13 to drive the piston 21 to push the finishing medium 8 and discharge it from the discharge end 190 of the cylinder block 18. The use of a hydraulic system driven by a motor not only provides a large thrust force but also high thrust precision.

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

[0070] The cylinder block 18 defines a space with a bottom plate and a top plate 19, which may be connected to the cylinder block 18 via bolts 7. The space between the piston 21 and the top plate 19 accommodates the finishing medium 8, and the opening in the top plate 19 is the outlet end 190 of the sealing system 102. The diameter ratio of the cylinder block 18 to the outlet end 190 is 10 to 32, which further increases the pressure of the finishing medium. Referring to FIG. 4, in some embodiments, the cross-sectional area ratio of the first-stage pipe 22 to the second-stage pipe 23 may be 1.2 to 1.8, which allows the finishing medium to be steadily and gradually increased in pressure while maintaining a saturated flow rate. In some embodiments, the multi-stage pipeline may further include a third stage pipeline 32 connected adjacently downstream of the second stage pipeline 22, with the cross-sectional area ratio between the second stage pipeline 22 and the third stage pipeline 32 being 1.2 to 1.8, and the length of the third stage pipeline 32 being shorter, as shown, like a joint. The use of a three-stage pipeline with a cross-sectional area ratio per stage of 1.2 to 1.8 allows for a stable and gradual pressure increase while maintaining a saturated flow rate, ensuring conditions for providing a stable pressure to the finishing medium and ensuring the strength, reliability, and service life of the transport pipeline system 103.

[0071] Referring to FIG. 4 , in some embodiments, the finishing device may include a tool 31 having at least two ports 310 corresponding to at least one inlet and at least one outlet of a workpiece 34. The tool 31 is stably fixed and attached to a table by a three-jaw chuck 33, and the workpiece 34 is clamped inside the tool 31 by a clamp bolt 30 of the tool. The ratio of the diameter of the third-stage pipeline 32 to the cross-sectional area of ​​the port of the tool 31 connected thereto may be 1.2 to 2.2, which has a beneficial effect similar to that described above, allowing for a stable and gradual pressure increase while maintaining a saturated flow rate. It should be noted that the upper limit of the ratio of the cross-sectional area of ​​the third-stage pipeline 32 to the cross-sectional area of ​​the port of the tool 31 connected thereto is 2.2, which may be higher than the upper limit of 1.8 for the proportion of the cross-sectional areas of the pipelines. The reason for this is explained below. That is, since tooling 31 is typically replaced frequently and the service life requirements are not as strict as those of pipelines, the upper limit of the cross-sectional area ratio can be set higher. In some embodiments, the ratio of the cross-sectional areas of the tooling port and the workpiece 34 port should be greater than 1 but not greater than 10, and both may be sealed with epoxy resin. The inventors discovered that if the ratio is greater than 1, the internal flow path of the workpiece can reach saturation flow. However, if the ratio is too large, the relief pressure at the workpiece 34 port increases, placing strict requirements on the strength and sealing of the connection between the port and the workpiece, and ultimately leading to safety accidents such as connection breakage. For this reason, the inventors discovered that the ratio should be set to 10 or less. It is understood that tooling 31 may have multiple spare ports 310 on it, each adapted to a different diameter of internal flow path of the workpiece. When one port is used, the other unused port may be connected and blocked with a bolt. The clamp bolts 30 of the jig tool 31 include an upper clamp bolt and a lower clamp bolt of the jig tool, and can clamp workpieces 34 of different specifications and sizes, and can be adjusted so that the ports of the jig tool and the ports of the internal flow path of the workpiece are on the same axis as the ports of the jig tool and the ports of the multi-stage pipeline.

[0072] The inventors have discovered that by adopting the multi-stage pipeline transport pipeline system introduced in the above embodiment, a thrust system configuration that combines a hydraulic pump and a vertical plunger pump, and a configuration that combines vertical and horizontal types, high precision can be achieved (error is 0.01 MPa) even when providing a thrust of 50 MPa or more, and pressure fluctuations during operation are small, falling within the range of ±0.1%, making it possible to fully and effectively realize the finishing method introduced above.

[0073] 2 and 3, the inventors have discovered that the sealing system 102 is particularly important because it is necessary to provide a large pressure to the finishing medium, and that while ensuring sealing, it is also necessary to ensure smooth movement of the piston 21 along the inner wall of the cylinder block 18.

[0074] The piston 21 has at least a first groove 211 and a second groove 210 extending from the top to the bottom. The sealing system 102 further includes a seal ring located between the piston 21 and the cylinder block 18, the seal ring including a first seal ring 17 in the first groove 211 and a second seal ring 170 in the second groove 210. The radial gap between the piston 21 and the cylinder block 18 is 1 mm to 2.5 mm. By adopting a configuration with multiple grooves and multiple seal rings and a gap between the piston and the cylinder block of 1 mm to 2.5 mm, the first seal ring can filter abrasive particles in a two-phase flow, while the second seal ring seals a pure liquid phase, such as an aqueous liquid phase, thereby achieving good sealing performance against the finishing medium. The inventors have discovered that a gap range of 1 mm to 2.5 mm can ensure that the piston can move smoothly along the wall of the cylinder block 18 to push and discharge the finishing medium 18 while maintaining good sealing effect.

[0075] 3, the first groove 211 of the piston 21 is a separate component, the upper surface 212 of the piston body is flat, and the cover plate 20 is detachably mounted thereon. The cover plate 20 has a slope 201 on its outer periphery, and the slope 201 and the upper surface of the piston 21 form a single-sided inclined groove to form the first groove 211. The second groove 210 is mounted on the side wall of the piston, and the first seal ring 17 is made of a hard polymer material, and the second seal ring 170 is made of a soft polymer material. The principle behind this will be described below. The inventors discovered that under high pressure, abrasive particles would enter the gap between the cylinder wall and the seal ring and scratch the seal ring, regardless of how well the first seal ring sealed. Therefore, the single-sided inclined groove and hard seal ring are provided to guide the abrasive particles so that they can independently enter / slide into the first seal ring 17, forming an insert-type self-sealing structure. For this reason, the first seal ring 17 is made of a hard polymer material. Furthermore, after most of the abrasive particles have independently entered the first seal ring 17, what should be sealed by the second seal ring 170 is the liquid phase in the two-phase flow, so the soft second seal ring 170 provides sealing. The reason why the first groove 211 should be a separate component is as follows: The inventors discovered that because the first seal ring 17 is made of a hard polymer structure and is subject to high pressure, if a groove were provided directly on the side wall of the piston, the first seal ring 17 would not be able to be secured. Therefore, the first groove 211 is made of a separate component. During assembly, the first seal ring is placed on the top surface 212 of the body of the piston 21, and then the cover plate 20 is placed on and tightened with the bolts 7. In some embodiments, the angle of inclination of the single-sided inclined groove, i.e., the inclination surface 201, is greater than 60° to provide sufficient clamping force.

[0076] In some embodiments, the specific materials for the first seal ring 17 and the second seal ring 170 may be a polymer material for the first seal ring that satisfies the following requirements: a flexural modulus of 1.9 GPa to 3.6 GPa, an elongation of 60% to 120%, and a Knoop hardness of 90 HK to 100 HK. This allows the first seal ring 17 to have a certain rigidity and be less likely to develop significant distortion, and also have good surface self-lubrication, low compression shrinkage, and the ability for the abrasive grains to easily embed into the material and then slide easily through the material after embedding. The polymer material of the second seal ring 170 has a flexural modulus of 0.2 GPa to 0.25 GPa, an elongation rate of 300% to 380%, and a flexural strength of 80 to 100 MPa, so that the second seal ring 170 has good elasticity and can generate obvious distortion. It also has a significant compression contraction length to provide sealing ability against aqueous substances, and it must also have high flexural strength; otherwise, it will be prone to breakage after bending during movement.

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

[0078] 3, the second groove 211 may have at least two grooves, including a first sub-groove 2111 and a second sub-groove 2112, from the top to the bottom, where the ratio of the depth of the second sub-groove 2112 to the depth of the first sub-groove 2111 is 1.2 to 1.5. A third sub-groove 2113 may be further provided toward the bottom of the second sub-groove 2112, or more sub-grooves may be provided. The ratio of the depth of the second sub-groove 2112 to the depth of the third sub-groove 2113 is 1.2 to 1.5. The second seal rings 170 corresponding to the first sub-groove 2111, the second sub-groove 2112, and the third sub-groove 2113 are seal rings 16, 15, and 14, respectively, and their function is to seal water. The grooves may be trapezoidal, which facilitates processing and fixing of the seal rings. The second sub-groove 2112 is deeper than the adjacent first sub-groove 2111 and third sub-groove 2113, which has the following beneficial effects: it can provide reliable multi-stage sealing against the fluid phase of the finishing medium. The first sub-groove 2111 provides a preliminary seal, the second sub-groove 2112 provides a complete seal, and the third sub-groove 2113 provides a reliable seal.

[0079] Referring now to FIG. 3 , in some embodiments, the cylinder wall of the cylinder block 18 is coated with a coating having a thickness of 50 μm to 220 μm and a hardness of 1500 HV to 2200 HV, made of one or a combination of oxide, carbide, boride, and nitride ceramics. Its beneficial effect is to ensure a reliable sealing effect. The principle behind this coating is as follows: The inventors discovered that during operation, the two-phase flow of fluid and abrasive particles moves at high speed. The abrasive particles get trapped between the seal ring and the cylinder block, rubbing against the cylinder wall. Scratches caused by friction on the cylinder wall can lead to complete failure of the sealing system and leakage of the fluid phase. Therefore, a hardened cylinder wall is essential. The process for achieving the coating described above can also solve the wear resistance issue of the cylinder wall by thermally spraying a special WC coating onto the bore of the cylinder block. The specific composition of the WC coating thermally sprayed onto the cylinder block is as follows: The WC powder particle size is 15-100 μm, the WC powder content is greater than 85%, the molybdenum powder content is 1-4%, the silicon powder content is 1-5%, and the boron powder content is 1-5%. 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 acts as a reinforcing phase in the WC coating, increasing its strength and hardness. During spraying, the particle temperature is below 1500°C, which reduces the amount of thermal deformation of the cylinder block after heating at low temperatures and ensures the accuracy of the final cylinder block size. The spraying distance is 10-50 mm, ensuring the coating's bonding strength greater than 100 MPa at a short spraying distance. 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, which prevents the relative movement between the piston and the cylinder block from generating a rolling force that would damage the coating and cause peeling, thereby further ensuring the life of the sealing system and the reliability of the sealing effect.To achieve this effect, the coating may be subjected to surface honing, with the honing tool being a zirconium oxide ceramic tool, and the honing speed being less than 80 r / min. The low speed ensures that the coating does not peel, chip or fall off during honing.

[0080] Referring now to FIG. 2, the finishing apparatus 10 may further include a diagnostic device, which includes a flow velocity sensor and / or a flow rate sensor and a pressure sensor for detecting the flow velocity and / or flow rate and pressure of the finishing medium to diagnose the status of the finishing process. The sensor need only be positioned close to the upstream end of the workpiece 34, and the principle behind this is described below. The inventors discovered that when the finishing process proceeds normally, the flow velocity, flow rate, and pressure of the finishing medium at the upstream end of the fine internal flow passage are affected only by the shape of the internal flow passage and the surface quality of the internal flow passage. The flow resistance and flow rate of the internal flow passage itself generate a reaction force that directly acts on the flow velocity, flow rate, and pressure at the upstream end. Because the downstream end of the internal flow passage is larger than the cross-sectional area of ​​the internal flow passage, the finishing medium flows freely without load relative to the downstream end after flowing out of the internal flow passage, and the downstream end of the internal flow passage does not affect the flow velocity, flow rate, and pressure at the upstream end. Therefore, simply measuring the change in the entry velocity at the upstream end can reflect the processing quality of the internal flow passage.

[0081] The pressure sensors include a high-sensitivity piezoelectric quartz sensor 28 and a high-resolution multi-channel data collector 27. They monitor data from pressure gauges 29 at multiple ports in real time and fully record the quasi-static and highly dynamic pressure processes during the completion process, thereby obtaining accurate flow resistance data for each flow path and ensuring optimal completion. The flow velocity and / or flow rate sensors include a velocity flow meter 24, a velocity flow piezoelectric sensor 25, and a velocity flow data collector 26. They employ ultrasonic measurement principles, using Doppler-based ultrasonic flow meters to synchronize the velocity and flow rates of multiple ports. Ultrasonic non-contact measurement completely prevents damage to the velocity flow meter caused by two-phase flow, greatly improving the response sensitivity of the entire system and optimizing completion times.

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

Claims

1. a thrust system; a sealed system including a piston and a cylinder block fitted to the piston and containing a finishing medium for performing finishing, wherein the thrust system is connected to one end of the piston and provides a driving force to the sealed system to push the finishing medium out of an outlet end of the cylinder block; a transport pipeline system for transporting the finishing medium contained in a corresponding closed system to a port of the internal flow work where finishing is to be performed, the transport pipeline system having an upstream end connected to an outlet end of the closed system and a downstream end for discharging the finishing medium for finishing the internal flow work; a recovery system comprising a recovery vessel, a recovery line, a return line, a power assembly, and a control valve assembly, wherein the control valve assembly comprises a first valve and a second valve, the recovery vessel is in communication with the workpiece via the recovery line and in communication with the sealing system via the return line, the first valve selectively communicating the sealing system with an external low-pressure environment, the second valve located in the return line selectively communicating the recovery vessel with the sealing system, the power assembly is in communication with the recovery vessel, and is capable of providing power to the recovery vessel so that finishing medium in the recovery system returns to the cylinder block; the piston has at least a first groove and a second groove on a side wall between the top and bottom, the sealing system further includes a seal ring located between the piston and a cylinder block, the seal ring including a first seal ring provided in the first groove and a second seal ring provided in the second groove, and a radial gap between the piston and the cylinder block is 1 mm to 2.5 mm; a piston having a flat upper surface and a removably mounted cover plate thereon, the cover plate having a sloped outer peripheral surface, the first groove being formed between the outer peripheral surface of the cover plate and the upper surface of the piston, the second groove being formed in a side wall of the piston, the first seal ring being made of a hard material, and the second seal ring being made of a soft material.

2. The first valve is a nozzle flapper valve, and the finishing device has a first state and a second state, wherein: In the first state, a finishing medium is transported from the sealing system to the transport pipeline system, and the finishing medium contained in the sealing system acts on a nozzle of the nozzle flapper valve to close the nozzle flapper valve, and the second valve is closed; 2. The finishing apparatus of claim 1, wherein in the second state, the nozzle flapper valve is opened to connect the sealed system to an external low-pressure environment, the transport of finishing medium from the sealed system to the transport pipeline system is stopped, the action of the nozzle flapper valve on the nozzle by the finishing medium contained in the sealed system is stopped, and the second valve is opened, and the power assembly applies pressure to the collection container up to a first pressure, thereby creating a pressure difference between the first pressure and the external low-pressure environment between the collection container and the sealed system.

3. 3. The finishing device of claim 2, wherein the second valve is a solenoid valve, the control valve assembly further comprising a sensor for detecting a mass of finishing medium in a collection container, and the solenoid valve is opened or closed as a result of the mass detected by the sensor.

4. 4. The finishing device of claim 3, wherein the sensor is a gravity sensor and the collection container is located higher than the sealing system.

5. 2. The finishing device according to claim 1, wherein the collection container is a transparent container, and the finishing medium contained therein can be seen from the outside.

6. 6. The finishing device of claim 5, wherein the container wall of the collection container has volume graduations.

7. 2. The finishing device according to claim 1, wherein the collection container is provided with a thermometer or a viscometer.

8. 10. The finishing device of claim 1, further comprising a diagnostic device, the diagnostic device having a flow rate and / or flow rate sensor and a pressure sensor for detecting the flow rate and / or flow rate and pressure of the finishing medium.

9. 2. The finishing device according to claim 1, wherein the material of the first seal ring satisfies the following requirements: a flexural modulus of 1.9 GPa to 3.6 GPa, an elongation rate of 60% to 120%, and a Knoop hardness of 90 HK to 100 HK; and the material of the second seal ring satisfies the following requirements: a flexural modulus of 0.2 GPa to 0.25 GPa, an elongation rate of 300% to 380%, and a flexural strength of 80 MPa to 100 MPa.

10. 2. The finishing device of claim 1, wherein the finishing medium comprises a liquid phase and a solid phase, the viscosity of the liquid phase being less than 1000 cP, the solid phase comprising abrasive grains, and the workpiece to be finished is a workpiece with a fine internal flow passage, a diameter of 3 mm or less, and a length-to-diameter ratio of 50:1 or more.

11. A finishing method for an internal passage workpiece, comprising: employing a finishing device as described in any one of claims 1 to 10; the finishing medium comprises a liquid phase and a solid phase; the viscosity of the liquid phase is less than 1000 cP; the solid phase comprises abrasive grains; the workpiece to be finished is a fine internal passage workpiece; the diameter of the fine internal passage is 3 mm or less; and the length-to-diameter ratio 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 through the fine internal passage at a flow velocity greater than 5 m / s; and the flow rate of the finishing medium flowing into one end of the fine internal passage is set to a critical flow rate allowed by the diameter of the fine internal passage so that the liquid pressure inside the fine internal passage is maintained at a pressure-maintaining state.

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