Servo valve forming method and system, storage medium and servo valve

Abstract

The invention discloses a forming method and system of a servo valve, a storage medium and the servo valve, and relates to the technical field of additive manufacturing, the forming method of the servo valve specifically comprises the following steps that ceramic powder and metal powder are provided, a preset method is used for enabling the metal powder to wrap the ceramic powder, and ceramic composite powder is obtained; a servo valve three-dimensional model is constructed, the three-dimensional model is sliced, and slicing information is obtained; laying the ceramic composite powder layer by layer based on the slicing information, and spraying a binder one by one for bonding to obtain a green body; and the green body is subjected to curing of at least one thermal cycle, powder cleaning, degreasing of at least one thermal cycle and sintering of at least one thermal cycle in sequence, and the target servo valve is obtained. The ceramic composite powder is obtained by coating the ceramic powder with the metal powder, the combination of the coated ceramic powder is promoted by melting during sintering, the combination difficulty is reduced, and the material which is high in hardness, high in toughness and complex in structure and takes the ceramic as a main body is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a forming method and system of a servo valve, a storage medium and a servo valve. Background Art

[0002] As a precision hydraulic control element, the servo valve can accurately control movement, respond quickly, and work stably for a long time under harsh environmental conditions. These excellent performances are inseparable from the material and structural design and advanced manufacturing of its power system and actuator mechanism. At present, the requirements for the life and stability of servo valves are getting higher and higher. Under such long-term stable working requirements, the strength, wear resistance and fatigue life of the materials used in the power system and actuator mechanism of the servo valve must be improved to avoid material wear and cracking affecting the performance of the servo valve, and to ensure that the servo valve can meet the number of cycles of the actuator mechanism even in extreme environments.

[0003] Ceramic materials are an important candidate for servo valves because of their excellent thermal stability, wear resistance, corrosion resistance, chemical stability, high strength and high hardness. However, there are few reports on ceramic materials for servo valves. This is because there are two major obstacles to using ceramic materials for servo valves: ceramic materials have low toughness and are very hard and brittle. Although they can avoid performance degradation due to wear in the servo valve actuator, there is a high probability of direct failure due to fragmentation; ceramic materials are difficult to form. In the face of the current generative design innovation of servo valves, traditional processes can no longer meet the needs, and technologies such as ceramic additive manufacturing are required. Additively formed ceramic materials also have problems such as easy deformation, difficult sintering, and failure and damage during the forming process.

[0004] Therefore, how to solve the two major obstacles of ceramic materials, reduce the difficulty of bonding ceramic materials, improve the toughness of ceramic materials, and apply ceramic materials to the preparation of servo valves has become a difficult problem that needs to be overcome urgently. Summary of the invention

[0005] The main purpose of the present invention is to provide a servo valve forming method, system, storage medium and servo valve, aiming to reduce the difficulty of combining ceramic materials and improve the toughness of the manufactured structure.

[0006] To achieve the above-mentioned purpose, the present invention provides a forming method of a servo valve, and the preparation method specifically comprises the following steps: Providing ceramic powder and metal powder, and using a preset method to coat the ceramic powder with the metal powder to obtain a ceramic composite powder; Construct a servo valve three-dimensional model, slice the three-dimensional model and obtain slice information; Laying the ceramic composite powder layer by layer based on the slicing information and spraying a binder one by one to bond the ceramic composite powder to obtain a green body; The green body is sequentially subjected to at least one thermal cycle of solidification, powder cleaning, at least one thermal cycle of debinding and at least one thermal cycle of sintering to obtain a target servo valve.

[0007] In one embodiment, the predetermined method for coating the ceramic powder with the metal powder comprises one or more of mechanical mixing, solid phase reaction, chemical deposition, electrodeposition, vapor deposition, precipitation, heterogeneous nucleation, and spray pyrolysis.

[0008] In one embodiment, the ceramic composite powder has a sphericity of 50%-99%, a particle size range of 1 nm-100 μm, and a ceramic powder content of 55%-95%.

[0009] In one embodiment, the ceramic composite powder is laid and the binder is sprayed one by one based on the process parameters of powder laying speed, binder infiltration time, binder drying time, and powder laying vibration rate. The powder laying speed ranges from 10 mm / s to 1000 mm / s, the binder infiltration time ranges from 0.5 s to 120 s, the binder drying time ranges from 0.5 s to 300 s, and the powder laying vibration rate is 100 rpm to 10000 rpm.

[0010] In one embodiment, laying of ceramic composite powder is specifically carried out based on the parameters of powder layer thickness, binder feeding circuit times, droplet spacing, printing rate, and binder injection frequency, wherein the layer thickness ranges from 10 μm to 200 μm; the binder feeding circuit times ranges from 1 to 20 times; the droplet spacing is 10 μm to 300 μm in the horizontal and vertical directions of the same horizontal plane; the printing rate ranges from 10 mm / s to 2000 mm / s; and the binder injection frequency ranges from 1 kHz to 50 kHz.

[0011] In one embodiment, the spraying of the adhesive is performed based on the adhesive droplet volume, the predicted filling rate, the number of nozzles, and the resolution parameters, wherein the adhesive droplet volume ranges from 30 pL to 500 pL, the predicted filling rate ranges from 15% to 95%, the number of nozzles is 128 to 2048, and the resolution is 100 dpi to 1200 dpi.

[0012] In one embodiment, the curing temperature of a single thermal cycle is between 25°C and 800°C, and the single curing time is between 0.5 s and 300 s; the debinding temperature of a single thermal cycle is between 200°C and 900°C, and the single debinding time is between 30 min and 24 h; the sintering temperature of a single thermal cycle is between 600°C and 2000°C, and the predicted filling rate ranges from 15% to 95%.

[0013] The present invention also provides a servo valve forming system, the servo valve forming system comprising: a powder coating module, used to provide ceramic powder and metal powder, and use a preset method to make the metal powder coat the ceramic powder to obtain a ceramic composite powder; A three-dimensional construction module is used to construct a three-dimensional model of the servo valve, slice the three-dimensional model and obtain slice information; A green body forming module is used to lay the ceramic composite powder layer by layer based on the slicing information and spray the binder one by one to bond the ceramic composite powder to obtain a green body; The post-processing module is used to sequentially perform at least one thermal cycle of solidification, powder cleaning, at least one thermal cycle of debinding and at least one thermal cycle of sintering on the green body to obtain a target servo valve.

[0014] The present invention further provides a storage medium, in which a computer program is stored, wherein the computer program is configured to execute the forming method of the servo valve as described above when running.

[0015] The present invention further provides a servo valve, comprising a valve body, a valve core arranged in the valve body and a valve sleeve covering the outer surface of the valve core, wherein the valve body, the valve core and the valve sleeve are respectively prepared using the forming method of the servo valve as described above.

[0016] The technical solution of the present invention obtains ceramic composite powder by coating ceramic powder with metal powder. The addition and coating of metal powder enhance the toughness of the ceramic composite powder, while the high hardness characteristics of the internal ceramic powder remain unchanged. The ceramic composite powder is formed into a green body by constructing a three-dimensional model, slicing, and printing based on the slicing information. The target servo valve is obtained through a multi-stage curing, degreasing and sintering process. The metal powder is melted by high temperature during the degreasing and sintering process to form a molten state, and after cooling, the bonding between them is more firm, reducing the difficulty of combining ceramic materials. The melting point of metal powder is lower than that of ceramic, so that the sintering temperature is reduced and the stability of the sintered structure is improved. The sintering difficulty is greatly reduced and the sintering effect is enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 A flow chart of the steps of the forming method of the servo valve provided by the present invention; Figure 2A microscopic schematic diagram of steel powder coated with silicon nitride powder in the forming method of the servo valve provided by the present invention; Figure 3 A microscopic schematic diagram of a steel-coated silicon nitride ceramic composite material in a forming method of a servo valve provided by the present invention; Figure 4 A schematic structural diagram of a forming system for a servo valve provided by the present invention; Figure 5 A schematic diagram of the structure of the storage medium provided by the present invention; Figure 6 This is a schematic structural diagram of the servo valve provided by the present invention.

[0019] Description of Figure Numbers: 100. Forming system of servo valve; 11. Powder coating module; 12. Three-dimensional construction module; 13. Green forming module; 14. Post-processing module; 200. Storage medium; 21. Computer program; 300, servo valve; 31, valve body; 32, valve core; 33, valve sleeve.

[0020] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that if there are directional indications (such as up, down, left, right, front, back, etc.) involved in the embodiments of the present invention, the directional indication is only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly. Unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, and it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0023] In addition, if there are descriptions of "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. Moreover, the terms "include", "comprise", or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article, or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article, or device. In the absence of further restrictions, the elements defined by the sentence "include one..." do not exclude the presence of other identical elements in the process, method, article, or device including the elements. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes, taking "A and / or B" as an example, including scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0024] As a precision hydraulic control element, the servo valve can accurately control movement, respond quickly, and work stably for a long time under harsh environmental conditions. These excellent performances are inseparable from the material and structural design and advanced manufacturing of its power system and actuator mechanism. At present, the requirements for the life and stability of servo valves are getting higher and higher. Under such long-term stable working requirements, the strength, wear resistance and fatigue life of the materials used in the power system and actuator mechanism of the servo valve must be improved to avoid material wear and cracking affecting the performance of the servo valve, and to ensure that the servo valve can meet the number of cycles of the actuator mechanism even in extreme environments.

[0025] Ceramic materials are an important candidate for servo valves because of their excellent thermal stability, wear resistance, corrosion resistance, chemical stability, high strength and high hardness. However, there are few reports on ceramic materials for servo valves. This is because there are two major obstacles to using ceramic materials in servo valves: ceramic materials have low toughness and are very hard and brittle. Although they can avoid performance degradation due to wear in the servo valve actuator, there is a chance of direct failure due to fragmentation; ceramic materials are difficult to form. In the face of the current generative design innovation of servo valves, traditional processes can no longer meet the needs, and technologies such as ceramic additive manufacturing are required. Additively formed ceramic materials also have problems such as easy deformation, difficult sintering, and failure and damage during the forming process.

[0026] Therefore, how to solve the two major obstacles of ceramic materials, reduce the difficulty of bonding ceramic materials, improve the toughness of ceramic materials, and apply ceramic materials to the preparation of servo valves has become a difficult problem that needs to be overcome urgently.

[0027] The main purpose of the present invention is to provide a servo valve forming method, system, storage medium and servo valve, aiming to reduce the difficulty of combining ceramic materials and improve the toughness of the manufactured structure.

[0028] See also Figure 1 To achieve the above-mentioned purpose, the present invention provides a forming method of a servo valve, and the preparation method specifically comprises the following steps: S1: providing ceramic powder and metal powder, and using a preset method to coat the ceramic powder with the metal powder to obtain a ceramic composite powder; S2: construct a servo valve three-dimensional model, slice the three-dimensional model and obtain slice information; S3: laying the ceramic composite powder layer by layer based on the slicing information and spraying a binder one by one to bond the ceramic composite powder to obtain a green body; S4: performing solidification, powder cleaning, debinding, and sintering of the green body in sequence for at least one thermal cycle to obtain a target servo valve.

[0029] It should be noted that curing, debinding and sintering all need to be achieved through thermal cycles. By subjecting the same process to thermal cycles with different temperature gradients, the progress of the process can be accelerated, making the time used shorter than the time at conventional temperatures, thereby greatly improving efficiency.

[0030] It can be understood that using metal powder to coat ceramic powder can make the metal powder melt and combine into one during sintering, promote the combination of the coated ceramic powder, reduce the difficulty of combination, and obtain a material with high hardness, high toughness and complex structure with ceramic as the main body; The conventional method of coating metal powder with ceramic powder is to enhance the hardness of the composite material and change the performance of the metal-based material after forming, but it does not promote its forming process. The sintering temperature of the outer layer of ceramic powder is higher, and it will not make the composite material easier to sinter.

[0031] Optionally, the preset method for coating the ceramic powder with the metal powder includes one or more of mechanical mixing, solid phase reaction, chemical deposition, electrodeposition, vapor deposition, precipitation, heterogeneous nucleation, and spray pyrolysis.

[0032] In one embodiment, the ceramic composite powder has a sphericity of 50%-99%, a particle size range of 1 nm-100 μm, and a ceramic powder content of 55%-95%.

[0033] Optionally, the sphericity of the ceramic composite powder may be 50%, 52%, 59%, 63%, 67%, 70%, 75%, 81%, 89%, 92%, 96%, 99%; It should be noted that 100% sphericity is the ideal sphericity. The sphericity of powder obtained by conventional methods is difficult to achieve this standard. In addition, in the present invention, the quality of the sphericity has relatively little effect on the final sintered product, so no absolute restriction is made.

[0034] Optionally, the particle size of the ceramic composite powder may be 1 nm, 10 nm, 35 nm, 50 nm, 87 nm, 100 nm, 231 nm, 356 nm, 589 nm, 694 nm, 762 nm, 883 nm, 950 nm, 1 μm, 6 μm, 10 μm, 23 μm, 35 μm, 40 μm, 56 μm, 61 μm, 73 μm, 89 μm, 95 μm, 100 μm; Optionally, the content of ceramic powder in the ceramic composite powder can be 55%, 60%, 63%, 71%, 82%, or 95%.

[0035] Preferably, in a specific embodiment of the present invention, the sphericity of the ceramic composite powder is 80%, the particle size range is 300 nm to 10 μm, and the content of ceramic powder in the ceramic composite powder is 60% to 90%.

[0036] In one embodiment, laying ceramic composite powder and spraying binder one by one are performed based on process parameters such as powder laying speed, binder infiltration time, binder drying time, and powder laying vibration rate. Among them, the powder spreading speed range is 10 mm / s~1000 mm / s, the binder infiltration time range is 0.5 s~120 s, the binder drying time range is 0.5 s~300 s, and the powder spreading vibration rate is 100 rpm~10000 rpm.

[0037] Alternatively, the powder spreading speed can be 10 mm / s, 17 mm / s, 23 mm / s, 29 mm / s, 35 mm / s, 42 mm / s, 53 mm / s, 67 mm / s, 88 mm / s, 91 mm / s, 99 mm / s, 100 mm / s, 173 mm / s, 268 mm / s, 379 mm / s, 452 mm / s, 513 mm / s, 685 mm / s, 786 mm / s, 844 mm / s, 976 mm / s, 1000 mm / s; Optionally, the adhesive infiltration time can be 0.5 s, 1.3 s, 1.9 s, 2.6 s, 3.0 s, 7.8 s, 10 s, 15 s, 28.2 s, 39 s, 45 s, 52 s, 64.8 s, 78 s, 86 s, 99.7 s, 100 s, 112 s, 120 s; Optionally, the adhesive drying time can be 0.5 s, 1.2 s, 2.8 s, 6.7 s, 10.0 s, 15 s, 28 s, 49 s, 61 s, 72 s, 80 s, 94 s, 102 s, 156 s, 178 s, 200 s, 221 s, 259 s, 284 s, 291 s, 300 s; Optionally, the powder spreading vibration rate can be 100 rpm, 120 rpm, 159 rpm, 184 rpm, 256 rpm, 353 rpm, 592 rpm, 821 rpm, 913 rpm, 1353 rpm, 213 rpm, 3522 rpm, 4856 rpm, 5921 rpm, 6745rpm, 7498 rpm, 8957 rpm, 9314 rpm, 10000 rpm; Preferably, in a specific embodiment of the present invention, the powder spreading speed is 100 mm / s, the binder infiltration time is 80 s, the binder drying time is 10 s, and the powder spreading vibration rate is 2000 rpm.

[0038] In one embodiment, the laying of ceramic composite powder is specifically based on the powder layer thickness, the number of binder feeding cycles, the droplet spacing, the printing rate, and the binder injection frequency parameters, and the layer thickness ranges from 10 μm to 200 μm; the number of binder feeding cycles ranges from 1 to 20 times; the droplet spacing is 10 μm to 300 μm in the horizontal and vertical directions of the same horizontal plane; the printing rate ranges from 10 mm / s to 2000 mm / s; and the binder injection frequency ranges from 1 kHz to 50 kHz.

[0039] Alternatively, the layer thickness can range from 10 μm, 16 μm, 23 μm, 30 μm, 46 μm, 57 μm, 62 μm, 75 μm, 89 μm, 95 μm, 109 μm, 116 μm, 124 μm, 130 μm, 142 μm, 157 μm, 164 μm, 172 μm, 181 μm, 195 μm, 200 μm; Optionally, the number of adhesive feeding rounds may be 1, 3, 5, 9, 10, 14, 17, or 20 times; Optionally, the droplet spacing in the horizontal and vertical directions of the same horizontal plane is 10 μm, 23 μm, 56 μm, 79 μm, 91 μm, 100 μm, 137 μm, 146 μm, 168 μm, 183 μm, 200 μm, 230 μm, 266 μm, 272 μm, 285 μm, and 300 μm; Optionally, the printing rate can be 10 mm / s, 35 mm / s, 56 mm / s, 89 mm / s, 100 mm / s, 357 mm / s, 578 mm / s, 823 mm / s, 1000 mm / s, 1220 mm / s, 1469 mm / s, 1875 mm / s, 2000 mm / s; Optionally, the binder jetting frequency may be 1 kHz, 8 kHz, 13 kHz, 26 kHz, 35 kHz, 44 kHz, 50 kHz; Preferably, in a specific embodiment of the present invention, the layer thickness is 100 μm, the number of adhesive feeding cycles is 5 times, the droplet spacing is 200 μm in both the horizontal and vertical directions on the same horizontal plane, the printing rate is 200 mm / s, and the adhesive spraying frequency is 30 kHz.

[0040] It should be noted that during the powder laying process, the temperature of the powder bed is 25℃-100℃, and the temperature of the compacting roller is 25℃-50℃. The temperature of the powder bed and the temperature of the compacting roller can directly provide the temperature for laying powder and spraying binder, thereby ensuring temperature control during the overall powder forming process, which is conducive to the efficient printing process and efficient shaping of the powder.

[0041] In one embodiment, the spraying of adhesive further includes adhesive droplet volume, predicted filling rate, number of nozzles, and resolution parameters, wherein the adhesive droplet volume ranges from 30 pL to 500 pL, the predicted filling rate ranges from 15% to 95%, the number of nozzles is 128 to 2048, and the resolution is 100 dpi to 1200 dpi.

[0042] Optionally, the volume of the binder droplet can be 30 pL, pL, 65 pL, 94 pL, 156 pL, 239 pL, 328 pL, 436 pL, 500 pL; The predicted filling rate is the ratio of the binder filling rate in the gaps of ceramic composite powder to the gap size, which is used to reflect the filling saturation degree of the gaps.

[0043] Optionally, the predicted fill rate may be 15%, 30%, 44%, 52%, 67%, 72%, 88%, 90%, 95%; Optionally, the number of nozzles may be 128, 256, 384, 512, 768, 1024, 1536, or 2048; It should be noted that the spray holes are mostly symmetrical in design, so most of them are designed in an even number. Modular spray holes are usually used for spraying, which makes disassembly easy and realizes the convenient and fixed increase of the number of spray holes.

[0044] Optionally, the resolution can be 100 dpi, 200 dpi, 300 dpi, 400 dpi, 500 dpi, 600 dpi, 700 dpi, 800 dpi, 900 dpi, 1000 dpi, 1200 dpi; Preferably, in a specific embodiment of the present invention, the volume of the binder droplet is 300 pL, the predicted filling rate is 60%, the number of nozzles is 512, and the resolution is 800 dpi.

[0045] In one embodiment, the curing temperature of a single thermal cycle is 25°C-800°C, and the single curing time is 0.5 s-300 s; the debinding temperature of a single thermal cycle is 200°C-900°C, and the single debinding time is 30 min-24 h; the sintering temperature of a single thermal cycle is 600°C-2000°C, and the single sintering time is 15 min-24 h.

[0046] It should be noted that the binder is completely removed after the curing and degreasing process, so that the formed blank is completely combined together during the high-temperature sintering process to enhance its structural properties. The optimal temperature required in different processes is different, so multiple thermal cycle treatments can be used, using different temperature gradients for curing, degreasing and sintering, so that the optimal temperature is provided within the optimal time period, thereby achieving the best processing effect, thereby saving costs and processing time.

[0047] Specifically, in different post-processing processes, there are no restrictions on the temperature and time of a single thermal cycle. The thermal cycle process may vary depending on the size and structure of the formed green body, so it shall be based on actual needs.

[0048] The technical solution of the present invention obtains ceramic composite powder by coating ceramic powder with metal powder. The addition and coating of metal powder enhance the toughness of the ceramic composite powder, while the high hardness characteristics of the internal ceramic powder remain unchanged, thereby obtaining a servo valve with high hardness, high toughness and complex structure with ceramic as the main body. The ceramic composite powder is formed into a green body by constructing a three-dimensional model, slicing and printing based on the slicing information, and the target servo valve is obtained through a multi-stage curing, degreasing and sintering process. The metal powder is melted by high temperature during the degreasing and sintering process to form a molten state, and after cooling, the bonding between them is more firm, reducing the difficulty of combining ceramic materials. The melting point of metal powder is lower than that of ceramic, so that the sintering temperature is reduced and the stability of the sintered structure is improved. The sintering difficulty is greatly reduced and the sintering effect is enhanced.

[0049] For details, please combine Figure 1-Figure 3 In one embodiment, a servo valve of a ceramic composite material is formed. The raw material is steel-coated silicon nitride powder. After sintering, the material density reaches 97%, the open porosity is less than 2%, the measured four-point bending strength reaches 921 MPa, and the Young's modulus is about 236 GPa. Compared with silicon nitride ceramics, the bending strength is higher and the Young's modulus is smaller, achieving the effect of strengthening and toughening.

[0050] In the steel-coated silicon nitride powder, silicon nitride is Si3N4, accounting for 90%~95%. It is a powder of 5 μm~45 μm and has a sphericity of about 65%. The sinterable steel grade of the external coating layer is 316L. The two materials are mixed by a composite method of chemical vapor deposition and mechanical ball milling to form a shell-core structure with a film-like and granular morphology.

[0051] After the raw material powder, binder and forming data files are prepared, the bonding forming begins. The bonding forming parameters are as follows:

[0052] The material is cured layer by layer, the powder bed temperature is high, and 21 seconds are reserved for curing each layer after each layer of binder is sprayed. After forming, a bonded body is obtained without an additional curing process. The bonded body is taken out and double-stage degreasing and double-stage sintering are performed. For specific parameters, please see the table below:

[0053] The dense steel-clad silicon nitride ceramic composite servo valve body, valve sleeve, valve core and motor rotor were sintered using the parameters in the above table.

[0054] It should be noted that the main purpose of using multi-stage curing / debinding / sintering is to reduce overall energy consumption and time. The combination of multiple curing methods has certain benefits: such as layer-by-layer curing + drying curing. Compared with single-stage drying curing, layer-by-layer curing is equivalent to leaving a little curing time after each layer is printed. The subsequent drying curing can be reduced / shortened in terms of temperature and time. Using two-stage curing will also make the curing more thorough and avoid damage to the green body during transportation.

[0055] See also Figure 4 The present invention further proposes a servo valve forming system 100, which uses the servo valve forming method as described above. Since the servo valve forming system 100 adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0056] The servo valve forming system 100 includes a powder coating module 11, which is used to provide ceramic powder and metal powder, and use a preset method to make the metal powder coat the ceramic powder to obtain a ceramic composite powder; The three-dimensional construction module 12 is used to construct a three-dimensional model of the servo valve, slice the three-dimensional model and obtain slice information; The green body forming module 13 is used to lay the ceramic composite powder layer by layer based on the slicing information and spray the binder one by one to bond the ceramic composite powder to obtain a green body; The post-processing module 14 is used to sequentially perform at least one thermal cycle of solidification, powder cleaning, at least one thermal cycle of debinding and at least one thermal cycle of sintering on the green body to obtain a target servo valve.

[0057] See also Figure 5 The present invention further proposes a storage medium 200, in which a computer program 21 is stored, wherein the computer program 21 is configured to execute the forming method of the servo valve as described above when running.

[0058] Since the storage medium 200 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0059] See also Figure 6 The present invention further proposes a servo valve 300, including a valve body 31, a valve core 32 arranged in the valve body 31 and a valve sleeve 33 covering the outer surface of the valve core 32. The valve body 31, the valve core 32 and the valve sleeve 33 are respectively prepared using the forming method of the servo valve as described above.

[0060] Since the servo valve 300 is prepared by the above-mentioned servo valve forming method and adopts all the technical solutions of the servo valve forming method, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0061] It should be understood that the "one implementation method" or "one embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present invention. Therefore, "in one implementation method" or "in one embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. Those skilled in the art should also be aware that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0062] In various embodiments of the present invention, it should be understood that the size of the serial numbers of the above-mentioned processes does not mean the necessary order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0063] The flow chart and block diagram in the accompanying drawings of the present invention illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which is determined based on the functions involved. It should be particularly noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs a specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0064] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for forming a servo valve, characterized in that: The preparation method specifically comprises the following steps: Providing ceramic powder and metal powder, and using a preset method to coat the ceramic powder with the metal powder to obtain a ceramic composite powder; Construct a servo valve three-dimensional model, slice the three-dimensional model and obtain slice information; Laying the ceramic composite powder layer by layer based on the slicing information and spraying a binder one by one to bond the ceramic composite powder to obtain a green body; The green body is sequentially subjected to at least one thermal cycle of solidification, powder cleaning, at least one thermal cycle of debinding and at least one thermal cycle of sintering to obtain a target servo valve.

2. The method for forming a servo valve according to claim 1, wherein: The preset method for coating ceramic powder with metal powder includes one or more of mechanical mixing, solid phase reaction, chemical deposition, electrodeposition, vapor deposition, precipitation, non-uniform nucleation, and spray pyrolysis.

3. The forming method of the servo valve according to claim 1, characterized in that: The ceramic composite powder has a sphericity of 50%-99%, a particle size range of 1 nm-100 μm, and a ceramic powder content of 55%-95%.

4. The forming method of the servo valve according to claim 1, wherein laying the ceramic composite powder and spraying the binder one by one is performed based on the process parameters of powder laying speed, binder infiltration time, binder drying time, and powder laying vibration rate, characterized in that: The powder spreading speed ranges from 10 mm / s to 1000 mm / s, the binder infiltration time ranges from 0.5 s to 120 s, the binder drying time ranges from 0.5 s to 300 s, and the powder spreading vibration rate ranges from 100 rpm to 10000 rpm.

5. The forming method of the servo valve according to claim 1, wherein the ceramic composite powder is laid based on the thickness of the powder layer, the number of cycles of the binder feeding, the droplet spacing, the printing rate, and the binder spraying frequency parameters, characterized in that: The layer thickness ranges from 10 μm to 200 μm; the number of adhesive feeding cycles ranges from 1 to 20 times; the droplet spacing in the horizontal and vertical directions of the same horizontal plane is 10 μm to 300 μm; the printing rate ranges from 10 mm / s to 2000 mm / s; and the adhesive jetting frequency ranges from 1 kHz to 50 kHz.

6. The method for forming a servo valve according to claim 1, wherein: The adhesive spraying is performed based on the adhesive droplet volume, predicted filling rate, number of nozzles, and resolution parameters, where the adhesive droplet volume ranges from 30 pL to 500 pL, the predicted filling rate ranges from 15% to 95%, the number of nozzles is 128 to 2048, and the resolution is 100 dpi to 1200 dpi.

7. The method for forming a servo valve according to claim 1, wherein: The curing temperature of a single thermal cycle is between 25°C and 800°C, and the single curing time is between 0.5 s and 300 s; the debinding temperature of a single thermal cycle is between 200°C and 900°C, and the single debinding time is between 30 min and 24 h; the sintering temperature of a single thermal cycle is between 600°C and 2000°C, and the single sintering time is between 15 min and 24 h.

8. A servo valve forming system, characterized in that: The servo valve forming system comprises: a powder coating module, which is used to provide ceramic powder and metal powder, and use a preset method to make the metal powder coat the ceramic powder to obtain a ceramic composite powder; A three-dimensional construction module is used to construct a three-dimensional model of the servo valve, slice the three-dimensional model and obtain slice information; A green body forming module is used to lay the ceramic composite powder layer by layer based on the slicing information and spray the binder one by one to bond the ceramic composite powder to obtain a green body; The post-processing module is used to sequentially perform at least one thermal cycle of solidification, powder cleaning, at least one thermal cycle of debinding and at least one thermal cycle of sintering on the green body to obtain a target servo valve.

9. A storage medium, characterized in that: The storage medium stores a computer program, wherein the computer program is configured to execute the forming method of the servo valve as described in any one of claims 1 to 7 when running.

10. A servo valve, comprising a valve body, a valve core arranged in the valve body and a valve sleeve covering the outer surface of the valve core, characterized in that: The valve body, valve core and valve sleeve are respectively prepared by using the forming method of the servo valve according to any one of claims 1 to 7.

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