Detection Method Based on Precise Ceramic Core Mosaic Process

Abstract

The detection method based on the precise splicing process of ceramic cores includes the steps of fixing the front end and the rear end of the ceramic core body on the tooling, inserting them into each other, using a 3D scanner to scan the geometric shape of the ceramic core, injecting AB glue at the first point of the splicing part, using a suction pump to suck air negatively through the ventilation holes to accelerate fixation and promote the dispersion and filling of the AB glue in the joints. After fixation, use a 3D scanner to scan the geometric shape of the ceramic core again, inject heat-resistant glue at the second point of the splicing part, and use the suction pump to suck air negatively through the ventilation holes again. Inject sintering glue at the third point of the splicing part, place the aluminum matrix ceramic core with the sintering glue injected on the lower tooling, send it into a high-temperature furnace, take it out after high-temperature sintering, and use a 3D scanner to scan the geometric shape of the ceramic core. Through the comparison of the scanning data and the negative pressure suction process under the tooling positioning, ensure the stable combination at the splicing part, avoid defects caused by sintering stress, achieve precise splicing, and greatly improve the quality of subsequent casting.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation casting, and particularly to detection technology. Background Art

[0002] In production, it is found that almost all ceramic cores have certain deformation during the sintering process. The turbine valve ceramic core has aluminum-based ceramic core bodies arranged on both sides, and the aluminum-based ceramic core bodies on both sides are connected by an intermediate body. The intermediate body includes a hollow pipeline and a distribution plate. Among them, the deformation amount at the splicing joint of the aluminum-based ceramic core body is larger, and it may cause deviation in insertion. While the deformation amounts of the intermediate body and the distribution plate are relatively small and usually can be ignored. During the splicing process, due to the brittleness of the ceramic material and the precise requirements of the complex flow channel, how to achieve high-precision positioning of the front part and the rear part of the aluminum-based ceramic core body, and ensure the stable combination at the splicing joint after positioning, and avoid defects such as microcracks, pores, and impurities caused by sintering stress, has become a key technical problem affecting the quality of castings.

[0003] The deformation amount of the ceramic core after sintering is usually detected individually by using mold inspection tools, coordinate measuring machines, laser measurement, etc. The workload is large and the efficiency is low. At the same time, there are large differences among the core individuals, and the detection data cannot accurately represent the sintering deformation degree of the core material. Summary of the Invention

[0004] The purpose of the present invention is to provide a detection method based on the precise splicing process of ceramic cores to solve the problems existing in the above-mentioned prior art.

[0005] The above technical purpose of the present invention is achieved through the following technical solutions:

[0006] A detection method based on the precise splicing process of ceramic cores includes preparing ceramic core bodies to be butted. The ceramic core bodies include a front end of the ceramic core body and a rear end of the ceramic core body. At the splicing joint of the front end and the rear end of the ceramic core body, a first point, a second point, and a third point for injecting glue are arranged from front to back;

[0007] S1: Fix the front end and the rear end of the ceramic core body on the fixture, insert them into each other, and use a 3D scanner to scan the geometric shape of the ceramic core to obtain the first set of 3D scan data;

[0008] S2: Inject AB glue at the first point of the splicing joint to complete pre-fixation;

[0009] S3: After pre-fixation, use a suction pump to suck negative pressure through the vent holes to accelerate fixation and promote the dispersion and filling of the AB glue into the gaps;

[0010] S4: After fixation is completed, perform secondary positioning and calibration. Use a 3D scanner to scan the geometric shape of the ceramic core to obtain the second set of 3D scan data. If it is qualified, proceed to the next step; if it is unqualified, disassemble and return to S2;

[0011] S5: After the secondary calibration, inject heat-resistant glue at the second point of the splicing joint.

[0012] S6: Use the air extractor to suck negative pressure on the vent hole again to accelerate fixation and promote the dispersed filling of the heat-resistant glue into the joints.

[0013] S7: After fixation, inject sintering glue at the third point of the splicing joint.

[0014] S8: Lower the tooling of the aluminum matrix ceramic core injected with sintering glue into the high-temperature furnace.

[0015] S9: Take it out after high-temperature sintering, use a 3D scanner to scan the geometric shape of the ceramic core, and obtain the third set of 3D scan data.

[0016] The 3D scan data is the three-dimensional coordinate data of the points on the outer surface of the ceramic core.

[0017] Compare the first set of 3D scan data with the three-dimensional coordinate data of the points on the outer surface of the ceramic core obtained by 3D modeling, calculate the insertion deviation of the ceramic core body, and ensure that the pre-positioning meets the requirements.

[0018] Compare the second set of 3D scan data with the first set of 3D scan data to detect whether the shrinkage or expansion of the splicing joint is caused after the colloid is cured.

[0019] Compare the third set of 3D scan data with the previous two sets to ensure that the splicing sintering accuracy meets the requirements.

[0020] By adopting the above technical solution, the high-precision structured light 3D scanning technology is used for the whole-process quality monitoring, including the X-ray three-dimensional microscopy system Micro-CT. Micro-CT mainly consists of a micro-focus X-ray source, a high-resolution CCD camera, a precision turntable and special scanning software, and can achieve a measurement accuracy of ±0.02 mm. The initial assembly inspection corresponding to S1 is immediately scanned for the first time after the front and rear ends of the ceramic core body are inserted and fixed. The ceramic core body on the assembled tooling needs to be installed on the turntable at room temperature, and the complete point cloud is obtained by multi-angle scanning of 0° / 90° / 180° / 270°. The statistical outlier algorithm is used to filter out environmental noise points and retain the valid data points, and then the ICP algorithm is used to register the scan data with the 3D model, and the initial gap of the splicing joint and the alignment of the flow channel are analyzed emphatically as the reference data for the subsequent process.

[0021] For the AB glue curing monitoring from S2 to S4, after the AB glue injection and negative pressure curing are completed, a secondary scan is required. Compare the first set of data, calculate the volume change of the colloid filling area, enhance the point cloud density in the splicing seam area through adaptive sampling, and then perform three-dimensional deviation analysis and verification to ensure that the runner deformation ≤ 0.03 mm and the glue seam continuity ≥ 95%. When unqualified items occur, melt the AB glue with a flame gun and return to step S2 for rework;

[0022] For the heat-resistant glue stage detection from S5 to S7, establish a time series analysis model for three sets of data, monitor the cumulative deformation trend, calculate the possible risks during the sintering process, and verify the concentration coefficient of thermal stress during this process.

[0023] The point cloud data processing uses the professional 3D detection software Geomagic Control X. First, filter the noise points in the collected data, use the statistical outlier removal algorithm to eliminate the environmental interference points, and then perform point cloud registration. Adopt the ICP (Iterative Closest Point) algorithm based on feature points to align the scanned data with the 3D model. The registration accuracy is controlled within 0.01 mm. For the key splicing area, use the adaptive sampling technology to increase the point cloud density to ensure the deformation detection accuracy of the ceramic core after sintering and avoid defects such as microcracks, pores, and impurities caused by sintering stress;

[0024] The tooling includes a rear support frame, a front support frame, and a V-shaped support. The front support frame includes a front tightening mechanism. Before the secondary positioning and calibration, the first positioning and calibration need to be carried out when installing the upper tooling. First, use a laser tracker to perform full-size calibration on the tooling, measure the relative position between the front support frame and the rear support frame, calibrate the stroke of the front tightening mechanism, set three reference balls for auxiliary calibration on the base of the tooling. After inserting the front end and the rear end of the ceramic core, place them on the tooling, perform positioning through the tooling, and then make the pre-positioning points set on the ceramic core correspond to the reference balls pre-set on the base of the tooling to determine the relative distance between them, so as to complete the corresponding calibration;

[0025] At the same time, in the precise splicing process, there is an opening at the rear side of the rear end of the aluminum-based ceramic core. The air extractor is connected to the opening through a hose. As the air is extracted, a negative pressure environment of -0.3~-0.6 bar can be formed on the bonding surface, so that the front end and the rear end of the aluminum-based ceramic core are closely attached under the action of the air pressure difference. The negative pressure suction makes it easier for the AB glue to fill the surface unevenness of the ceramic core surface, reduces the interface pores. This process has high compatibility, can avoid mechanical clamps from damaging the brittle ceramic core, extracts the volatile components while the glue cures, reduces the generation of bubbles, realizes high strength, low defects, and high consistency of the ceramic core bonding, and can effectively improve the strength while stabilizing the quality.

[0026] In a further embodiment, an outer step structure is provided at the rear side of the front end of the ceramic core body, and an inner step structure is provided at the front side of the rear end of the ceramic core body, which cooperates with the outer step structure;

[0027] The inner step structure includes a first - stage step, a second - stage step, and a third - stage step with diameters gradually increasing from front to back;

[0028] A plurality of AB - glue coating grooves are circumferentially and equally spaced on the first - stage step;

[0029] A plurality of high - temperature - resistant glue coating grooves are circumferentially and equally spaced on the second - stage step;

[0030] A plurality of sintering - glue coating grooves are circumferentially and equally spaced on the third - stage step;

[0031] An air - flow channel is provided on the first - stage step, which communicates with the high - temperature - resistant glue coating groove of the second - stage step and the interior of the front end of the ceramic core body, and no glue is applied in the air - flow channel;

[0032] A ventilation hole communicating with the air - flow channel is provided at the rear side of the rear end of the ceramic core body;

[0033] AB - glue injection ports called the first point, high - temperature - resistant glue injection ports called the second point, and sintering - glue injection ports called the third point are spaced on the outer step structure.

[0034] By adopting the above - mentioned technical solution, three - stage stepped gluing is carried out, and AB glue, high - temperature - resistant glue, and sintering glue are respectively used for each stage, which can achieve the effect of staged curing. The AB glue on the first - stage step can quickly cure the front end and the rear end of the ceramic core body, provide initial strength, and resist slight vibration during handling and clamping. If problems in positioning of the ceramic core body are found during secondary positioning and calibration, without removing the tooling, the AB glue can be directly softened by a temperature of about 200 °C to disassemble and rework, thereby reducing the scrap rate;

[0035] The high - temperature - resistant glue on the second - stage step uses high - temperature - resistant epoxy resin. Epoxy resin has excellent thermal stability. By adding nano - scale heat - resistant fillers and a special curing agent system, it can complete preliminary curing under medium - temperature conditions of 80 - 120 °C, providing sufficient fixing strength. When the temperature continues to rise to the initial sintering stage of 300 - 600 °C, although most of the organic adhesives have started to decompose, this modified epoxy resin can still maintain a certain mechanical strength, preventing the front end and the rear end of the ceramic core body from loosening before reaching the high temperature required for sintering, effectively ensuring the final sintering quality;

[0036] The sintering glue on the third - level step uses silica sol. Silica sol is a stable colloidal solution formed by dispersing nanoscale silicon dioxide (SiO₂) particles in an organic solvent. When used as a binder, it can form a continuous SiO₂ glass phase at high temperatures, effectively filling the gaps between the core - molds and enhancing the bonding strength. As the temperature rises above 800 °C, the silanol groups (Si - OH) between the particles undergo a condensation reaction to form silicon - oxygen bonds (Si - O - Si), eventually forming a dense glass network structure. This process enables silica sol to exhibit excellent stability at high temperatures and can withstand the high - temperature environment during the sintering of aluminum - based ceramic core - molds (usually 1200 °C to 1600 °C). In addition, silica sol has high purity and does not introduce metal impurities, making it suitable for precision casting with strict requirements for chemical composition, such as the manufacturing of jet engine valve seats. A small amount of nano - zirconia filler is also mixed in the silica sol to improve the mechanical strength and thermal shock stability after sintering. Since the bonding strength of silica sol is relatively low at low - temperature stages, AB glue and heat - resistant glue are required for auxiliary fixation to ensure the relative positions of the core - molds before sintering;

[0037] An opening is provided at the rear side of the rear end of the ceramic core - body. The air extractor is connected to the opening through a hose. As air is extracted, a negative - pressure environment of - 0.3 to - 0.6 bar can be formed on the gluing surface, causing the front end and the rear end of the ceramic core - body to fit tightly under the action of the air - pressure difference. The negative - pressure suction makes it easier for the AB glue to fill the surface unevenness of the ceramic core, reducing the interface pores. This process has high process compatibility, can avoid mechanical jigs from damaging the brittle ceramic core, and can extract volatile components while the glue cures, reducing the generation of bubbles, achieving high strength, low defects, and high consistency in ceramic core gluing, and can effectively improve the strength while ensuring stable quality.

[0038] In a further embodiment, the tooling includes a base for supporting and fixing the ceramic core of the turbine valve, a front support frame for supporting and fixing the front - part split structure of the ceramic core - body on one side of the turbine - valve ceramic core, and a rear support frame for supporting and fixing the rear - part split structure of the ceramic core - body on one side of the turbine - valve ceramic core;

[0039] The rear support frame has a bracket for supporting and a stop block for preventing sliding provided behind the bracket;

[0040] Above the front support frame, there is a V - shaped bracket for carrying items;

[0041] It further includes a front - mounted tightening mechanism provided in front of the front support frame and fixed to the base;

[0042] The front - mounted tightening mechanism has a vertical column;

[0043] A horizontal screw hole is provided on the column, and a horizontal locking bolt is assembled in the horizontal screw hole;

[0044] The height of the horizontal screw hole is higher than the bottom of the V-shaped bracket and lower than the sum of the heights of the V-shaped bracket and the ceramic core body.

[0045] A cushion block is assembled at one end of the horizontal locking bolt facing the V-shaped bracket, and a lateral rotating handle is assembled at the other end facing away from the V-shaped bracket.

[0046] By adopting the above technical solution, the front pre-tightening mechanism drives the cushion block to abut against the front split structure of the ceramic core body through the axial advancement of the horizontal locking bolt. At the same time, the bracket and the stopper of the rear support frame form a combined structure of support and block. The bracket supports the ceramic core body at a horizontal height, while the stopper prevents the rear split structure of the ceramic core body from having an axial displacement during the splicing process. With the limiting effect of the V-shaped bracket, the clamping and fixing of the longitudinal axis are realized. The installation height of the horizontal locking bolt is precisely designed to ensure that the bolt does not interfere with the bracket and enable the cushion block to accurately act on the stress point of the ceramic core body. The lateral rotating handle enables the operator to achieve reliable locking with a small torque. This tooling realizes the fixation of the longitudinal axis through the front pre-tightening mechanism and the stopper on the rear support frame, and effectively reduces the problem of splicing misalignment caused by traditional tooling through cooperation with the V-shaped bracket.

[0047] In a further embodiment, each of the multiple AB glue application grooves includes a ramp groove and a slit groove.

[0048] The ramp groove is a groove with a ramp structure, and the depth of the ramp structure gradually becomes shallower from front to back.

[0049] The slit groove is connected to the rear end of the ramp groove and is in communication.

[0050] The depth of the slit groove is 0.1 mm to 0.3 mm.

[0051] A sponge layer is provided at the rear part of the slit groove.

[0052] At one end near the front side of the front end of the ceramic core body in each of the multiple high-temperature-resistant glue application grooves, a shielding and absorbing layer is provided to prevent the high-temperature-resistant glue from leaking into the rear end of the ceramic core body.

[0053] The shielding and absorbing layer adopts an asbestos mesh layer.

[0054] By adopting the above technical solution, the gradually changing depth design of the ramp groove ingeniously guides the flow of the adhesive, and in combination with the negative pressure suction process, ensures uniform distribution of the glue and no bubble residue. The ultra-thin slit groove precisely controls the glue layer thickness, ensuring both bonding strength and preventing glue overflow. The specially provided sponge layer plays a temporary isolation role during the curing stage and can be smoothly decomposed and discharged during high-temperature sintering. The asbestos mesh shielding layer provided at the front end of the temperature-resistant glue coating groove effectively prevents the glue from penetrating into non-target areas. This porous structure forms a selective barrier under negative pressure, ensuring sufficient infiltration of the glue while avoiding unnecessary glue waste. The entire system realizes efficient utilization and precise distribution of the glue through the synergistic effect of negative pressure suction and the special groove structure. This design significantly improves production efficiency and product reliability while ensuring process accuracy. The ingenious cooperation of each functional layer enables stable control throughout the entire process from room-temperature curing to high-temperature sintering.

[0055] In a further embodiment, in S8 stage, it is fed into the high-temperature furnace. A rotating table is provided in the high-temperature furnace, and a fixing device is provided on the rotating table. The valve seat ceramic core composed of ceramic cores is detachably installed on the fixing device.

[0056] In S9 stage, during the air-fuel stage of the high-temperature sintering, the air-fuel ratio of each section in the high-temperature furnace is set to 0.65:1.

[0057] In the preheating stage, the rotating table is started, and the temperature rises to 300 °C at a speed of 5 °C / min.

[0058] In the sintering stage, the temperature rises to 1400 °C at a speed of 10 °C / min.

[0059] In the soaking stage, the temperature is maintained at 1400 °C. During this period, the temperature uniformity is inspected through the infrared thermal imager of the high-temperature furnace.

[0060] In the cooling stage, the temperature is slowly cooled to 600 °C at a speed of 2 °C / min.

[0061] It is taken out after natural cooling to below 200 °C.

[0062] By adopting the above technical solution, the rotation of the rotating table ensures uniform heating of the ceramic core, avoiding deformation or stress concentration caused by local overheating. The stepped heating strategy with precise temperature control in combination with a specific air-fuel ratio can effectively control the sintering shrinkage rate. The real-time monitoring by the infrared thermal imager can timely adjust the temperature field distribution to avoid problems such as cold areas or uneven heating. The slow cooling process can eliminate thermal stress and prevent the ceramic core from cracking.

[0063] In a further embodiment, for the high-temperature sintering in S9 stage, a dynamic mixed atmosphere is required, which is divided into three stages in total:

[0064] Stage 1: When the temperature is from 0 to 600 °C, use N2 protection to remove the volatile components of the glue.

[0065] Stage 2: When the temperature is from 600 to 1400 °C, switch to Ar-5%H2 to promote the interfacial reaction.

[0066] Stage 3: When the temperature drops below 800 °C, switch to pure N2 protection to avoid hydrogen embrittlement.

[0067] By adopting the above technical solutions, the staged atmosphere regulation realizes multiple protections. In the nitrogen stage, organic volatiles are effectively removed to avoid carbon residue. The argon-hydrogen mixture reduces the surface oxides of the ceramic at high temperature and enhances the atomic diffusion ability. Finally, the nitrogen protection eliminates the risk of hydrogen embrittlement, greatly improving the fracture toughness and interfacial bonding strength of the material.

[0068] In a further embodiment, before inserting the front end and the rear end of the ceramic core body in the S1 stage, the front end and the rear end of the ceramic core body need to be placed in a negative pressure environment, argon is introduced, and a radio frequency power of 300 W is applied to ionize the argon to form high-energy plasma, which is used to increase the bonding strength after applying glue through surface treatment.

[0069] By adopting the above technical solutions, the active particles in the plasma will bombard the surface of the ceramic core, removing organic pollutants and the low-strength and low-activity thin layer regions formed on the material surface due to physical and chemical actions. At the same time, nano-scale roughness and polar groups such as -Si-OH are formed on its surface, changing the surface energy of the material from the original low-energy state to a high-energy state, thus greatly enhancing the wettability and bonding strength of the glue. And during sintering, some polar groups will further react with the ceramic matrix to form a more stable silicon-oxygen network.

[0070] In a further embodiment, the process of sucking air from the ventilation holes under negative pressure in the S3 stage is as follows:

[0071] S31: Connect the air extractor to the ventilation hole through a hose to ensure the airtightness of the interface.

[0072] S32: Start pumping air and increase the negative pressure step by step.

[0073] S33: Keep it at -0.6 bar for 3 - 5 minutes to make the glue penetrate evenly at the interface.

[0074] S34: Slowly release the pressure at a rate of 0.1 bar / min to prevent microcracks from being generated due to the rebound of the glue layer.

[0075] By adopting the above technical solution, the progressive pressure change can effectively avoid the problem of colloid splashing caused by instantaneous pressure difference, prevent the glue from being sucked into the air extraction system during the violent flow of the glue, ensure the uniform distribution of the glue layer, guarantee the complete coverage rate of the bonding surface, and the pressure holding stage is crucial for improving the bonding quality. After reaching -0.6 bar, it is maintained for 3 to 5 minutes. The continuous negative pressure is used to drive the glue to fully penetrate the micron-level pores on the ceramic surface, reducing the possible interface weaknesses after curing and significantly improving the airtightness and mechanical strength of the bonding surface.

[0076] In a further embodiment, after the high-temperature sintering in stage S9, it is taken out, and a 3D scanner is used to scan the geometric shape of the ceramic core, and the ceramic core is the ceramic core of the valve mounting seat;

[0077] Specifically: S91: Fix the ceramic core of the valve mounting seat on the rotating table, start the rotation, and generate 800 - 2000 projection images through X-ray scanning;

[0078] S92: According to the design model of the ceramic core of the valve mounting seat, measure the key dimensions and compare with the design tolerances;

[0079] S93: Detect the thin-wall area and analyze whether the wall thickness meets the requirements;

[0080] S94: Identify whether there are internal defects and unqualified features;

[0081] S95: Judge whether it is qualified. If it is qualified, enter the casting process. If it is unqualified, mark and eliminate it.

[0082] By adopting the above technical solution, with the cooperation of the micro-focus X-ray source and the high-speed detector, the system can achieve high-resolution imaging at the 5μm level, and can clearly identify defects such as micro-holes and inclusions inside the ceramic core. These microscopic defects are extremely easy to be missed in traditional two-dimensional X-ray detection. During the detection process, the ceramic core is fixed on a programmable rotating table, and a three-dimensional reconstruction is carried out through 800 - 2000 projection images at different angles to construct a complete digital model of the ceramic core. This multi-angle projection reconstruction technology enables the system to have a wall thickness measurement accuracy of 0.1 mm, and can accurately evaluate the wall thickness uniformity of each part of the ceramic core, especially for accurate measurement of the thin-wall area of complex internal cavity structures, and the efficiency far exceeds manual detection.

[0083] In a further embodiment, the rear side of the rear end of the ceramic core body is connected to the intermediate body;

[0084] The intermediate body includes a hollow pipeline and a distribution plate;

[0085] One end of the hollow pipeline is communicated with the ventilation hole at the rear end of the ceramic core body, and the other end of the hollow pipeline is communicated with the distribution plate;

[0086] A communication hole is provided at the rear side of the distribution plate. An iron pipe is provided at the communication hole. The distribution plate is communicated with an air extractor through the iron pipe. A hollow chamber is arranged inside the distribution plate, and the hollow chamber communicates the hollow pipeline with the inside of the iron pipe;

[0087] In the preheating stage, the air extractor performs negative pressure suction on the ceramic core of the valve mounting seat. The negative pressure starts from -0.2 bar and is gradually increased step by step to -0.4 bar, and is maintained at -0.4 bar for 50 to 60 minutes;

[0088] In the sintering stage, the negative pressure is rapidly increased to -0.8 bar and remains constant in the soaking stage;

[0089] In the cooling stage, the suction is stopped, and the negative pressure is gradually reduced to normal pressure to avoid cracking caused by thermal stress;

[0090] The negative pressure suction is used to discharge the heating residual substances of various adhesives.

[0091] By adopting the above technical scheme, the hollow pipeline of the intermediate body and the distribution plate structure constitute an efficient exhaust channel, enabling the negative pressure to act uniformly on the entire interior of the ceramic core. During high-temperature sintering, it can effectively discharge the residual substances generated by various adhesives during heating, including the volatiles during the curing of AB glue, the high-temperature decomposition products of heat-resistant glue, and the interfacial reaction gases of sintering glue. The progressive negative pressure increase in the preheating stage can gently discharge the volatiles of low-temperature glue while avoiding damage to the uncured glue layer structure. The high negative pressure in the sintering stage specifically solves the problem of discharging high-temperature decomposition gases. This dynamic regulation ensures that during the entire process from room-temperature curing to high-temperature sintering, the gases and residues generated by various adhesives can be discharged in a timely and effective manner. The design of canceling the negative pressure in the cooling stage not only completes the exhaust mission but also avoids thermal stress damage, providing a reliable guarantee for obtaining defect-free and high-strength ceramic core splicing parts.

[0092] In summary, the present invention has the following beneficial effects:

[0093] 1. Through the settings of the 3D scanner, with the help of a high-precision CT scanning system, a combination of a micro-focus X-ray source and a high-speed detector, and the motion control of a precision rotary table, it is possible to capture the complete internal structure of the ceramic core with a resolution of 5 μm. During the scanning process, the system will automatically collect 800 - 2000 projection images at different angles. After being processed by advanced image reconstruction algorithms, these data generate a digital model containing complete three-dimensional information. This model not only contains geometric dimension information but also clearly presents the tiny defects inside the material, providing a reliable data basis for subsequent quality assessment. In the quality analysis stage, a multi-level intelligent assessment strategy is adopted. First, the system will automatically register and compare the three-dimensional model reconstructed by CT with the 3D model to accurately measure the dimensional deviation of key parts. Second, the defect recognition algorithm based on deep learning will automatically mark and classify defects such as pores and inclusions inside the ceramic core. Finally, the system will comprehensively consider various detection indicators and automatically grade the product according to the preset quality standards. During this process, all detection data will be completely recorded and associated with specific production batches and process parameters, achieving the effect of providing a complete data chain for quality traceability;

[0094] 2. Through the settings of the inner stepped structure and the outer stepped structure, with the help of the precise cooperation between the inner stepped structure at the front end of the ceramic core body and the outer stepped structure at the rear end of the ceramic core body, as well as the glue injection holes provided on the outer stepped structure, in combination with the staged curing process of AB glue, heat-resistant glue, and sintering glue, it is possible to achieve high precision and high reliability in ceramic core splicing. The first-stage step uses AB glue for rapid curing to provide initial strength and resistance to handling vibration. The heat-resistant glue in the second-stage step maintains structural stability in the medium and high-temperature stages to prevent loosening before high-temperature sintering. The sintering glue in the third-stage step chemically bonds with the ceramic core matrix at high temperature to form a permanent connection. This process not only solves the problem of microcracks caused by the brittleness of ceramics in traditional splicing processes but also improves the process tolerance through the staged process. Combining with negative pressure suction can further eliminate interface pores, achieving a higher bonding strength;

[0095] 3. Through the settings of the ramp groove and the slit groove, by means of the gradually changing depth design of the ramp groove, the flow of the glue can be skillfully guided. Combined with the negative pressure suction process, it ensures that the glue is evenly distributed and there is no bubble residue. The ultra-thin slit groove precisely controls the thickness of the glue layer, which not only ensures the bonding strength but also avoids the overflow of the glue. The specially set sponge layer plays a temporary isolation role during the curing stage and can be smoothly decomposed and discharged during high-temperature sintering. The asbestos mesh shielding layer set at the front end of the heat-resistant glue coating groove effectively prevents the glue from penetrating into non-target areas. This porous structure forms a selective barrier under the action of negative pressure, which not only ensures the full infiltration of the glue but also avoids unnecessary glue waste. The entire system realizes the efficient utilization and precise distribution of the glue through the synergistic effect of negative pressure suction and the special groove structure. This design not only ensures the process accuracy but also significantly improves the production efficiency and product reliability. The ingenious cooperation of each functional layer enables stable control throughout the entire process from room temperature curing to high-temperature sintering. BRIEF DESCRIPTION OF THE DRAWINGS

[0096] Figure 1 is the overall schematic diagram of the ceramic core body in the detection method based on the precise splicing process of the ceramic core of the present invention;

[0097] Figure 2 is the internal structure schematic diagram of the ceramic core body in the detection method based on the precise splicing process of the ceramic core of the present invention, used to reflect the connection relationship between the front end and the rear end of the ceramic core body;

[0098] Figure 3 is the overall flow chart of the detection method based on the precise splicing process of the ceramic core of the present invention;

[0099] Figure 4 is the flow chart of negative pressure suction in the detection method based on the precise splicing process of the ceramic core of the present invention;

[0100] Figure 5 is the detection flow chart after the high-temperature sintering is completed in the detection method based on the precise splicing process of the ceramic core of the present invention.

[0101] In the figure, 1 is the front end of the ceramic core body; 2 is the rear end of the ceramic core body. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0102] The present invention will be further described in detail below with reference to the accompanying drawings.

[0103] Among them, the same components are denoted by the same reference numerals. It should be noted that the terms "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the attached Figure 1In the directions mentioned herein, the terms "bottom surface" and "top surface", "inner" and "outer" respectively refer to the directions towards or away from the geometric center of a specific component. Additionally, the terms "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this specification, "a plurality" means two or more, unless otherwise specifically and clearly defined.

[0104] As Figure 1 - Figure 5 shown, a detection method based on the precise splicing process of ceramic cores includes preparing ceramic core bodies to be butted. The ceramic core bodies include a front end 1 and a rear end 2 of the ceramic core body. At the splicing joint of the front end 1 and the rear end 2 of the ceramic core body, a first point, a second point, and a third point for injecting glue are arranged from front to back;

[0105] S1: Fix the front end 1 and the rear end 2 of the ceramic core body on the tooling, insert them into each other, and use a 3D scanner to scan the geometric shape of the ceramic core to obtain the first set of 3D scan data;

[0106] S2: Inject AB glue at the first point of the splicing joint to complete pre-fixing;

[0107] S3: After pre-fixing, use a suction pump to apply negative pressure suction to the vent holes to accelerate fixation and promote the dispersion and filling of the AB glue into the joints;

[0108] S4: After completion of fixation, perform secondary positioning and calibration, use a 3D scanner to scan the geometric shape of the ceramic core to obtain the second set of 3D scan data. If it is qualified, proceed to the next step; if it is unqualified, disassemble and return to S2;

[0109] S5: After secondary calibration, inject heat-resistant glue at the second point of the splicing joint;

[0110] S6: Use the suction pump to apply negative pressure suction to the vent holes again to accelerate fixation and promote the dispersion and filling of the heat-resistant glue into the joints;

[0111] S7: After completion of fixation, inject sintering glue at the third point of the splicing joint;

[0112] S8: Remove the aluminum matrix ceramic core with the injected sintering glue from the lower tooling and send it into a high-temperature furnace;

[0113] S9: Take it out after high-temperature sintering, use a 3D scanner to scan the geometric shape of the ceramic core to obtain the third set of 3D scan data;

[0114] The 3D scan data is the three-dimensional coordinate data of the points on the outer surface of the ceramic core;

[0115] Compare the first set of 3D scan data with the three-dimensional coordinate data of the points on the outer surface of the ceramic core obtained by 3D modeling, calculate the insertion deviation of the ceramic core body, and ensure that the pre-positioning meets the requirements;

[0116] Compare the second set of 3D scan data with the first set of 3D scan data to detect whether the shrinkage or expansion of the splicing seam is caused after the colloid is cured;

[0117] Compare the third set of 3D scan data with the previous two sets to determine that the splicing and sintering accuracy meets the requirements.

[0118] By adopting the above technical solution, high-precision structured light 3D scanning technology is used for the whole-process quality monitoring, including the X-ray three-dimensional microscopy system Micro-CT. Micro-CT mainly consists of a micro-focus X-ray source, a high-resolution CCD camera, a precision turntable and special scanning software, and can achieve a measurement accuracy of ±0.02mm. For the initial assembly inspection corresponding to S1, after the front and rear ends of the ceramic core body are inserted and fixed, the first scan is immediately carried out. The ceramic core body on the assembled tooling needs to be installed on the turntable at room temperature, and a complete point cloud is obtained through multi-angle scanning at 0° / 90° / 180° / 270°. The statistical outlier algorithm is used to filter out environmental noise points and retain valid data points. Then, the ICP algorithm is used to register the scan data with the 3D model, and the initial gap of the splicing seam and the alignment of the flow channel are analyzed emphatically as the reference data for the subsequent process;

[0119] For the AB glue curing monitoring from S2 to S4, after the AB glue injection and negative pressure curing are completed, a second scan is carried out to compare with the first set of data, calculate the volume change of the colloid filling area, enhance the point cloud density of the splicing seam area through adaptive sampling, and then carry out three-dimensional deviation analysis and verification to ensure that the deformation of the flow channel ≤0.03mm and the continuity of the glue seam ≥95%. When unqualified items appear, the AB glue is melted by a flame gun and the process returns to step S2 for rework;

[0120] For the temperature-resistant glue stage detection from S5 to S7, a time series analysis model of the three sets of data is established to monitor the cumulative deformation trend, calculate the possible risks during the sintering process, and verify the concentration coefficient of the thermal stress during this process;

[0121] The point cloud data processing uses the professional three-dimensional detection software Geomagic Control X. First, the noise points in the collected data are filtered, and the statistical outlier removal algorithm is used to eliminate the environmental interference points. Subsequently, point cloud registration is carried out, and the ICP (Iterative Closest Point) algorithm based on feature points is used to align the scan data with the 3D modeling. The registration accuracy is controlled within 0.01mm. For the key splicing area, the adaptive sampling technology is used to increase the point cloud density to ensure the deformation detection accuracy of the ceramic core body after sintering and avoid defects such as microcracks, pores and impurities caused by sintering stress;

[0122] The tooling includes a rear support frame, a front support frame and a V-shaped support. The front support frame includes a front pre-tightening mechanism. Before secondary positioning and calibration, the first positioning and calibration are required when installing the upper tooling. First, use a laser tracker to perform full-size calibration on the tooling, measure the relative position between the front support frame and the rear support frame, and calibrate the formation of the front pre-tightening mechanism. Three reference balls for auxiliary calibration are set on the base of the tooling. After inserting the front end 1 and the rear end 2 of the ceramic core body, place them on the tooling and position them through the tooling. Then, make the pre-positioning points set on the ceramic core body correspond to the reference balls pre-set on the base of the tooling to determine the relative distance between them, so as to complete the corresponding calibration;

[0123] At the same time, in the precise splicing process, an opening is provided at the rear side of the rear end 2 of the aluminum-based ceramic core body. The air extractor is connected to the opening through a hose. As the air is extracted, a negative pressure environment of -0.3 to -0.6 bar can be formed on the bonding surface, so that the front end 1 and the rear end 2 of the aluminum-based ceramic core body are closely attached under the action of the air pressure difference. The negative pressure suction makes the AB glue easier to fill the surface unevenness of the ceramic core, reducing the interface pores. This process has high compatibility, can avoid mechanical clamps from damaging the brittle ceramic core, extract the volatile components while the glue is curing, reduce the generation of bubbles, and achieve high strength, low defects and high consistency of the ceramic core bonding, which can effectively improve the strength while ensuring the quality.

[0124] In a further embodiment, an outer step structure is provided at the rear side of the front end 1 of the ceramic core body, and an inner step structure that cooperates with the outer step structure is provided at the front side of the rear end 2 of the ceramic core body. The inner step structure includes a first-stage step, a second-stage step and a third-stage step with diameters gradually increasing from front to back. Multiple AB glue application grooves are circumferentially and equally spaced on the first-stage step, multiple heat-resistant glue application grooves are circumferentially and equally spaced on the second-stage step, and multiple sintering glue application grooves are circumferentially and equally spaced on the third-stage step. An air flow channel is provided on the first-stage step, and the air flow channel communicates with the heat-resistant glue application groove on the second-stage step and the inside of the front end 1 of the ceramic core body, and no glue is applied in the air flow channel. A ventilation hole communicating with the air flow channel is provided at the rear side of the rear end 2 of the ceramic core body. An AB glue injection port called the first point, a heat-resistant glue injection port called the second point, and a sintering glue injection port called the third point are spaced on the outer step structure.

[0125] By adopting the above technical solution, three-level stepped gluing is used, and AB glue, heat-resistant glue, and sintering glue are respectively used for each level of the step, which can achieve the effect of staged curing. The AB glue on the first step can quickly cure the front end 1 and the rear end 2 of the ceramic core body, provide initial strength, and resist slight vibrations during handling and clamping. If problems with the positioning of the ceramic core body are found during secondary positioning and calibration, without removing the tooling, the AB glue can be directly softened by a temperature of about 200 °C to disassemble and rework, thereby reducing the scrap rate;

[0126] The heat-resistant glue on the second step uses heat-resistant epoxy resin. Epoxy resin has excellent thermal stability. By adding nano-scale heat-resistant fillers and a special curing agent system, it can complete preliminary curing under medium-temperature conditions of 80-120 °C, providing sufficient fixing strength. When the temperature continues to rise to the initial sintering stage of 300-600 °C, although most of the organic adhesives have started to decompose, this modified epoxy resin can still maintain a certain mechanical strength, preventing the front end 1 and the rear end 2 of the ceramic core body from loosening before reaching the high temperature required for sintering, effectively ensuring the final sintering quality;

[0127] The sintering glue on the third step uses silica sol. Silica sol is a stable colloidal solution formed by dispersing nano-scale silicon dioxide (SiO2) particles in an organic solvent. When used as a binder, it can form a continuous SiO2 glass phase at high temperatures, effectively filling the gaps between the cores and enhancing the bonding strength. As the temperature rises above 800 °C, the silanol groups (Si-OH) between the particles undergo a condensation reaction to form silicon-oxygen bonds (Si-O-Si), eventually forming a dense glass network structure. This process enables silica sol to exhibit excellent stability at high temperatures and can withstand the high-temperature environment during the sintering of aluminum-based ceramic cores (usually 1200 °C to 1600 °C). In addition, silica sol has high purity and does not introduce metal impurities, making it suitable for precision casting with strict requirements for chemical composition, such as the manufacture of jet engine valve seats. A small amount of nano-zirconia filler is also mixed in the silica sol to improve the mechanical strength and thermal shock stability after sintering. Since the bonding strength of silica sol is relatively low at low temperatures, AB glue and heat-resistant glue are required for auxiliary fixation to ensure the relative position of the cores before sintering;

[0128] There is an opening at the rear side of the rear end 2 of the ceramic core body. The air extractor is connected to the opening through a hose. As the air is extracted, a negative pressure environment of -0.3 to -0.6 bar can be formed on the bonding surface, so that the front end 1 and the rear end 2 of the ceramic core body are closely fitted under the action of the air pressure difference. The negative pressure suction makes it easier for the AB glue to fill the surface unevenness of the ceramic core surface, reducing the interface pores. This process has high compatibility, can avoid mechanical fixtures from damaging the brittle ceramic core, extract the volatile components while the glue cures, reduce the generation of bubbles, achieve high strength, low defects and high consistency in the bonding of the ceramic core, and can effectively improve the strength while ensuring the quality is stable.

[0129] In a further embodiment, the tooling includes a base for supporting and fixing the turbine valve ceramic core, a front support frame for supporting and fixing the front partial structure of the ceramic core body on one side of the turbine valve ceramic core, and a rear support frame for supporting and fixing the rear partial structure of the ceramic core body on one side of the turbine valve ceramic core. The rear support frame has a bracket for supporting and a stopper for blocking sliding arranged behind the bracket. There is a V-shaped bracket for carrying items above the front support frame. It also includes a front pre-tightening mechanism arranged in front of the front support frame and fixed on the base. The front pre-tightening mechanism has a vertical column, a horizontal screw hole is arranged on the column, a horizontal locking bolt is assembled in the horizontal screw hole. The height of the horizontal screw hole is higher than the bottom of the V-shaped bracket and lower than the sum of the heights of the V-shaped bracket and the ceramic core body. A cushion block is assembled at one end of the horizontal locking bolt facing the V-shaped bracket, and a lateral rotating handle is assembled at the other end facing away from the V-shaped bracket.

[0130] By adopting the above technical solution, the front pre-tightening mechanism drives the cushion block to press against the front partial structure of the ceramic core body through the axial advancement of the horizontal locking bolt. At the same time, the bracket and the stopper of the rear support frame form a supporting and blocking combined structure. The bracket supports the ceramic core body at a horizontal height, and the stopper prevents the rear partial structure of the ceramic core body from having axial displacement during the splicing process. With the limiting effect of the V-shaped bracket, the clamping and fixing of the longitudinal axis are realized. The installation height of the horizontal locking bolt is precisely designed, which not only ensures that the bolt does not interfere with the bracket, but also enables the cushion block to act precisely on the stress point of the ceramic core body. The lateral rotating handle enables the operator to achieve reliable locking with a small torque. This tooling realizes the fixation of the longitudinal axis through the front pre-tightening mechanism and the stopper on the rear support frame, and effectively reduces the problem of splicing misalignment caused by traditional tooling through the cooperation with the V-shaped bracket.

[0131] In a further embodiment, the plurality of AB glue coating grooves include a slope groove and a slit groove. The slope groove is a groove with a slope structure. The depth of the slope structure gradually becomes shallower from front to back. The slit groove is connected to the rear end of the slope groove and is connected. The depth of the slit groove is 0.1mm~0.3mm. A sponge layer is provided at the rear of the slit groove. A shielding absorption layer is provided at one end of the front side close to the front end 1 of the ceramic core body in the plurality of heat-resistant glue coating grooves to prevent the heat-resistant glue from leaking into the rear end 2 of the ceramic core body. The shielding absorption layer adopts an asbestos mesh layer.

[0132] By adopting the above technical scheme, the gradient depth design of the slope groove cleverly guides the flow of glue, and cooperates with the negative pressure suction process to ensure that the glue is evenly distributed without bubble residue. The ultra-thin gap groove accurately controls the thickness of the glue layer, which not only ensures the bonding strength but also avoids glue overflow. The specially arranged sponge layer plays a temporary isolation role in the curing stage, and can be smoothly decomposed and discharged during high-temperature sintering. The asbestos mesh shielding layer set at the front end of the heat-resistant glue coating groove effectively prevents the glue from penetrating into non-target areas. This porous structure forms a selective barrier under the action of negative pressure, which not only ensures the full infiltration of the glue, but also avoids unnecessary waste of glue. The entire system realizes the efficient utilization and precise distribution of glue through the synergistic effect of negative pressure suction and special groove structure. This design significantly improves production efficiency and product reliability while ensuring process accuracy. The ingenious cooperation of various functional layers enables the whole process from room temperature curing to high-temperature sintering to be stably controlled.

[0133] In a further embodiment, the high-temperature furnace is sent to the S8 stage, and a rotary table is provided in the high-temperature furnace. A fixing device is provided on the rotary table. The valve mounting seat composed of the ceramic core body is detachably mounted on the fixing device. The high-temperature sintering in the S9 stage is in the air-fuel stage. The air-fuel ratio of each section in the high-temperature furnace is set to 0.65:1. In the preheating stage, the rotary table is turned on, and the temperature rises to 300 °C at a rate of 5 °C / min. In the sintering stage, the temperature rises to 1400 °C at a rate of 10 °C / min. In the equalization stage, the temperature is maintained at 1400 °C. During this period, the temperature uniformity is checked by the infrared thermal imager of the high-temperature furnace. In the cooling stage, the temperature is slowly cooled to 600 °C at a rate of 2 °C / min, and naturally cooled to below 200 °C and taken out.

[0134] By adopting the above technical solutions, the rotation of the turntable ensures that the ceramic core is heated evenly, avoiding deformation or stress concentration caused by local overheating. The precise temperature-controlled step-by-step heating strategy combined with a specific air-fuel ratio can effectively control the sintering shrinkage rate. Real-time monitoring by the infrared thermal imager can timely adjust the temperature field distribution to avoid cold areas or uneven heating. The slow cooling process can eliminate thermal stress and prevent the ceramic core from cracking.

[0135] In a further embodiment, the high temperature sintering in the S9 stage requires a dynamic mixed atmosphere and is divided into three stages:

[0136] Stage 1: When the temperature is from 0 to 600 °C, use N2 protection to remove the volatile components of the glue.

[0137] Stage 2: When the temperature is from 600 to 1400 °C, switch to Ar-5%H2 to promote the interfacial reaction.

[0138] Stage 3: When the temperature drops below 800 °C, switch to pure N2 protection to avoid hydrogen embrittlement.

[0139] By adopting the above technical solution, the multi-stage atmosphere regulation realizes multiple protections. In the nitrogen stage, organic volatiles are effectively removed, avoiding carbon residue. The argon-hydrogen mixture reduces the ceramic surface oxides at high temperature, enhancing the atomic diffusion ability. Finally, the nitrogen protection eliminates the risk of hydrogen embrittlement, greatly improving the fracture toughness and interfacial bonding strength of the material.

[0140] In a further embodiment, before inserting the front end 1 and the rear end 2 of the ceramic core body in the S1 stage, the front end 1 and the rear end 2 of the ceramic core body need to be placed in a negative pressure environment, argon is introduced, and a radio frequency power of 300 W is applied to ionize the argon to form high-energy plasma, which is used to increase the bonding strength after applying glue through surface treatment.

[0141] By adopting the above technical solution, the active particles in the plasma will bombard the surface of the ceramic core, removing organic pollutants and the low-strength and low-activity thin layer regions formed on the material surface due to physical and chemical actions. At the same time, nano-scale roughness and polar groups, such as -Si-OH, are formed on its surface, converting the surface energy of the material from the original low-energy state to a high-energy state, thereby greatly enhancing the wettability and bonding strength of the glue. And during sintering, some polar groups will further react with the ceramic matrix to form a more stable silicon-oxygen network.

[0142] In a further embodiment, in the S3 stage, a suction pump is used to suck the ventilation hole under negative pressure. The specific process is as follows:

[0143] S31: Connect the suction pump to the ventilation hole through a hose to ensure the airtightness of the interface.

[0144] S32: Start the suction and increase the negative pressure step by step.

[0145] S33: Maintain at -0.6 bar for 3 - 5 minutes to make the glue penetrate evenly at the interface.

[0146] S34: Slowly release the pressure at a rate of 0.1 bar / min to prevent microcracks from being generated due to the rebound of the glue layer.

[0147] By adopting the above technical solutions, the progressive pressure change can effectively avoid the problem of colloid splashing caused by instantaneous pressure difference, prevent the glue from being sucked into the air extraction system during the violent flow of the glue, ensure the uniform distribution of the glue layer, guarantee the complete coverage rate of the bonding surface, and the pressure holding stage is crucial for improving the bonding quality. After reaching -0.6 bar, it is maintained for 3 to 5 minutes, and the continuous negative pressure is used to drive the glue to fully penetrate the micron-level pores on the ceramic surface, reducing the possible interface weaknesses after curing and significantly improving the airtightness and mechanical strength of the bonding surface.

[0148] In a further embodiment, after the high-temperature sintering in the S9 stage, it is taken out, and a 3D scanner is used to scan the geometric shape of the ceramic core, and the ceramic core is the ceramic core of the valve mounting seat;

[0149] Specifically: S91: Fix the ceramic core of the valve mounting seat on the rotating table, start the rotation, and generate 800 - 2000 projection images through X-ray scanning;

[0150] S92: According to the design model of the ceramic core of the valve mounting seat, measure the key dimensions and compare with the design tolerances;

[0151] S93: Detect the thin-wall area and analyze whether the wall thickness meets the requirements;

[0152] S94: Identify whether there are internal defects and unqualified features;

[0153] S95: Judge whether it is qualified. If it is qualified, enter the casting process. If it is unqualified, mark and eliminate it.

[0154] By adopting the above technical solutions, with the cooperation of the microfocus X-ray source and the high-speed detector, the system can achieve high-resolution imaging at the 5μm level, and can clearly identify defects such as micro-holes and inclusions existing inside the ceramic core. These microscopic defects are extremely easy to be missed in traditional two-dimensional X-ray detection. During the detection process, the ceramic core is fixed on a programmable rotating table, and three-dimensional reconstruction is carried out through 800 - 2000 projection images at different angles to construct a complete digital model of the ceramic core. This multi-angle projection reconstruction technology enables the system to have a wall thickness measurement accuracy of 0.1 mm, and can accurately evaluate the wall thickness uniformity of each part of the ceramic core, especially for accurate measurement of the thin-wall area of complex internal cavity structures, and the efficiency far exceeds manual detection.

[0155] In a further embodiment, the rear side of the rear end 2 of the ceramic core is connected to an intermediate body. The intermediate body includes a hollow pipeline and a distribution plate. One end of the hollow pipeline is communicated with the vent hole of the rear end 2 of the ceramic core, and the other end of the hollow pipeline is communicated with the distribution plate. A communication hole is provided at the rear side of the distribution plate, and an iron pipe is provided at the communication hole. The distribution plate is communicated with an air extractor through the iron pipe. A hollow chamber is provided inside the distribution plate, and the hollow chamber communicates the inside of the hollow pipeline with the inside of the iron pipe. During the preheating stage, the air extractor performs negative pressure suction on the ceramic core of the valve seat. The negative pressure starts from -0.2 bar and is gradually increased step by step to -0.4 bar, and is maintained at -0.4 bar for 50 to 60 minutes. During the sintering stage, the negative pressure is quickly increased to -0.8 bar and is maintained constant during the soaking stage. During the cooling stage, the suction is stopped, and the negative pressure is gradually reduced to normal pressure to avoid cracking caused by thermal stress. The negative pressure suction is used to discharge the heating residual substances of various adhesives.

[0156] By adopting the above technical solution, the hollow pipeline and the distribution plate structure of the intermediate body constitute an efficient exhaust channel, enabling the negative pressure to act uniformly on the entire interior of the ceramic core. During high-temperature sintering, it can effectively discharge the residual substances generated during the heating process of various adhesives, including the volatile components during the curing of AB glue, the high-temperature decomposition products of heat-resistant glue, and the interfacial reaction gases of sintering glue. The progressive negative pressure increase in the preheating stage can gently discharge the volatiles of low-temperature glue while avoiding damage to the uncured glue layer structure. The high negative pressure in the sintering stage specifically solves the problem of discharging high-temperature decomposition gases. This dynamic regulation ensures that during the entire process from room-temperature curing to high-temperature sintering, the gases and residues generated by various adhesives can be discharged in a timely and effective manner. The design of canceling the negative pressure in the cooling stage not only completes the exhaust mission but also avoids thermal stress damage, providing a reliable guarantee for obtaining defect-free and high-strength ceramic core splicing parts.

[0157] Specific implementation process: First, the surface of the ceramic core is activated. The surface is cleaned by argon plasma bombardment and its surface energy is increased to create ideal conditions for subsequent gluing. Then, the ceramic core is scanned to obtain data for initial plugging. After the preprocessing is completed, the operator adopts a staged glue injection strategy and sequentially injects different types of adhesives using an automatic dispensing machine. The three-stage stepped structure is used to achieve the transition from temporary fixation to permanent bonding. During the glue injection process, scanning is also required to obtain corresponding data to ensure that there will be no problems such as offset at the splicing seam during the sintering process;

[0158] During the splicing process, a negative pressure environment established by the air extractor inside the ceramic core causes the two components to fit tightly under the action of the air pressure difference, and at the same time promotes the glue to fully fill the interface micro-gaps. To ensure the splicing accuracy, the whole process is equipped with a dual calibration system. The position accuracy is verified at key nodes through an optical measurement device, and problems can be repaired in time by local heating. In the curing stage, a progressive process is adopted, gradually transitioning from room temperature curing to high-temperature sintering. Each temperature range is matched with a specific protective atmosphere to optimize the interface bonding performance and prevent material deterioration;

[0159] Finally, through precise control of the temperature curve and dynamic switching of the protective gas, the sintering of the ceramic core is achieved. The components need to undergo strict CT scan detection. Through three-dimensional imaging technology, the internal quality and dimensional accuracy are comprehensively evaluated. After detecting that the internal shape meets the requirements and there are no various defects, the casting and molding are officially started.

[0160] In the embodiments disclosed in the present invention, terms such as "installation", "connection", "attachment", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "attachment" can be a direct attachment or an indirect attachment through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments disclosed in the present invention can be understood according to specific circumstances.

[0161] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A detection method based on the precise splicing process of ceramic cores, including preparing ceramic core bodies to be butt-jointed, characterized in that: The ceramic core body includes a front end (1) of the ceramic core body and a rear end (2) of the ceramic core body. At the joint of the front end (1) and the rear end (2) of the ceramic core body, a first point, a second point, and a third point for injecting glue are arranged from front to back; S1: Fix the front end (1) and the rear end (2) of the ceramic core body on the tooling, insert them into each other, and use a 3D scanner to scan the geometric shape of the ceramic core to obtain the first set of 3D scan data; S2: Inject AB glue at the first point at the joint to complete pre-fixation; S3: After pre-fixation, use a suction pump to apply negative pressure suction to the vent holes to accelerate fixation and promote the dispersion and caulking of the AB glue; S4: After fixation is completed, perform secondary positioning and calibration. Use a 3D scanner to scan the geometric shape of the ceramic core to obtain the second set of 3D scan data. If it is qualified, proceed to the next step. If it is unqualified, disassemble and return to S2; S5: After secondary calibration, inject heat-resistant glue at the second point at the joint; S6: Use the suction pump to apply negative pressure suction to the vent holes again to accelerate fixation and promote the dispersion and caulking of the heat-resistant glue; S7: After fixation is completed, inject sintering glue at the third point at the joint; S8: Remove the ceramic core with the sintering glue injected from the tooling and send it into a high-temperature furnace; S9: Take it out after high-temperature sintering, and use a 3D scanner to scan the geometric shape of the ceramic core to obtain the third set of 3D scan data; The 3D scan data is the three-dimensional coordinate data of the points on the outer surface of the ceramic core body; Compare the first set of 3D scan data with the three-dimensional coordinate data of the points on the outer surface of the ceramic core body obtained by 3D modeling, calculate the insertion deviation of the ceramic core body, and ensure that the pre-positioning meets the requirements; Compare the second set of 3D scan data with the first set of 3D scan data to detect whether the shrinkage or expansion of the splicing seam is caused after the colloid is cured; Compare the third set of 3D scan data with the previous two sets to determine that the splicing sintering accuracy meets the requirements.

2. The detection method based on the precise splicing process of ceramic cores according to claim 1, wherein: An outer step structure is arranged on the rear side of the front end (1) of the ceramic core body, and an inner step structure that cooperates with the outer step structure is arranged on the front side of the rear end (2) of the ceramic core body; The inner step structure includes a first-level step, a second-level step, and a third-level step with diameters gradually increasing from front to back; A plurality of AB glue application grooves are circumferentially and equally spaced on the first-level step; A plurality of heat-resistant glue application grooves are circumferentially and equally spaced on the second-level step; A plurality of sintering glue application grooves are circumferentially and equally spaced on the third-level step; An air flow channel is arranged on the first-level step. The air flow channel communicates with the heat-resistant glue application groove of the second-level step and the inside of the front end (1) of the ceramic core body, and no glue is applied in the air flow channel; A vent hole communicating with the air flow channel is arranged on the rear side of the rear end (2) of the ceramic core body; AB glue injection ports called the first point, heat-resistant glue injection ports called the second point, and sintering glue injection ports called the third point are spaced on the outer step structure.

3. The detection method based on the precise splicing process of ceramic cores according to claim 1, characterized in that: The tooling includes a base for supporting and fixing the ceramic core of the turbine valve, a front support frame for supporting and fixing the front split structure of the ceramic core body on one side of the turbine valve ceramic core, and a rear support frame for supporting and fixing the rear split structure of the ceramic core body on one side of the turbine valve ceramic core; The rear support frame comprises a bracket for supporting and a stopper arranged behind the bracket for preventing sliding; A V-shaped bracket for carrying items is provided above the front support frame; It also includes a front-mounted tightening mechanism arranged in front of the front support frame and fixed on the base; The front tightening mechanism has a vertical column; The column is provided with a horizontal screw hole, in which a horizontal locking bolt is installed; The height of the horizontal screw hole is higher than the bottom of the V-shaped bracket and lower than the sum of the heights of the V-shaped bracket and the ceramic core; The end of the horizontal locking bolt facing the V-shaped bracket is equipped with a cushion block, and the end facing away from the V-shaped bracket is equipped with a lateral rotation handle.

4. The detection method based on the precise splicing process of ceramic cores according to claim 2, wherein: The plurality of AB glue coating grooves each include a slope groove and a gap groove; The slope groove is a groove with a slope structure, and the depth of the slope structure gradually becomes shallower from front to back; The slit groove is butted against the rear end of the slope groove and is in communication with the slope groove; The depth of the slit groove is 0.1 mm to 0.3 mm; A sponge layer is arranged at the rear of the slit groove; A shielding absorption layer is provided at one end of the plurality of heat-resistant glue coating grooves near the front end (1) of the ceramic core body to prevent the heat-resistant glue from leaking into the rear end (2) of the ceramic core body; The shielding and absorbing layer is an asbestos mesh layer.

5. The detection method based on the precise splicing process of ceramic cores according to claim 1, characterized in that: In the S8 stage, the ceramic core is sent into a high-temperature furnace, wherein a rotary table is provided in the high-temperature furnace, and a fixing device is provided on the rotary table, and the ceramic core of the valve mounting seat composed of the ceramic core body is detachably mounted on the fixing device; The high temperature sintering in stage S9 is in the air-fuel stage, and the air-fuel ratio of each section in the high temperature furnace is set to 0.65:1; In the preheating stage, the rotary table was turned on and the temperature was increased to 300 °C at a rate of 5 °C / min; During the sintering stage, the temperature was increased to 1400 °C at a rate of 10 °C / min; During the soaking stage, the temperature was maintained at 1400 °C, during which the temperature uniformity was checked by an infrared thermal imager in the high-temperature furnace; In the cooling stage, the temperature was slowly cooled to 600 °C at a rate of 2 °C / min; Cool naturally to below 200 °C and take out.

6. The detection method based on the precise splicing process of ceramic cores according to claim 1, wherein: The high temperature sintering described in stage S9 requires a dynamic mixed atmosphere and is divided into three stages: Stage 1: At 0-600 °C, use N2 protection to remove the volatiles of the glue; Stage 2: At 600-1400 °C, switch to Ar-5%H2 to promote interface reaction; Stage 3: When the temperature drops below 800 °C, switch to pure N2 protection to avoid hydrogen embrittlement.

7. The detection method based on the precise splicing process of ceramic cores according to claim 1, characterized in that: Before the front end (1) and the rear end (2) of the ceramic core body are plugged together in the S1 stage, the front end (1) and the rear end (2) of the ceramic core body need to be placed in a negative pressure environment, argon gas is introduced, and 300W of radio frequency power is applied to ionize the argon gas to form high-energy plasma, which is used to increase the bonding strength after applying glue through surface treatment.

8. The detection method based on the precise splicing process of ceramic cores according to claim 1, characterized in that: In the S3 stage, the vacuum pump is used to suction the vents with negative pressure. The specific process is as follows: S31: Connect the vacuum pump to the vent hole through a hose to ensure the air tightness of the interface; S32: Start the vacuum and increase the negative pressure step by step; S33: Maintain at -0.6 bar for 3-5 minutes to allow the glue to penetrate evenly at the interface; S34: Slowly release pressure at a rate of 0.1 bar / min to prevent microcracks from occurring due to the rebound of the adhesive layer.

9. The detection method based on the precise splicing process of ceramic cores according to claim 1, wherein: After the high-temperature sintering in the S9 stage, take it out and use a 3D scanner to scan the geometric shape of the ceramic core, and the ceramic core is the ceramic core of the valve mounting seat; Specifically: S91: Fix the ceramic core of the valve mounting seat on the rotating table, start the rotation, and generate 800 - 2000 projection images through X-ray scanning; S92: Measure the key dimensions according to the design model of the ceramic core of the valve mounting seat, and compare with the design tolerances; S93: Detect the thin-walled area and analyze whether the wall thickness meets the requirements; S94: Identify whether there are internal defects and non-conforming features; S95: Judge whether it is qualified. If it is qualified, enter the casting process. If it is unqualified, mark and reject it.

10. The detection method based on the precise splicing process of ceramic cores according to claim 5, characterized in that: The rear side of the rear end (2) of the ceramic core body is connected to the intermediate body; The intermediate body includes a hollow pipeline and a distribution plate; One end of the hollow pipeline is communicated with the vent hole at the rear end (2) of the ceramic core body, and the other end of the hollow pipeline is communicated with the distribution plate; There is a communication hole provided at the rear side of the distribution plate, and an iron pipe is provided at the communication hole. The distribution plate is communicated with the air extractor through the iron pipe. There is a hollow chamber inside the distribution plate, and the hollow chamber communicates the inside of the hollow pipeline and the iron pipe; In the preheating stage, the air extractor performs negative pressure suction on the ceramic core of the valve mounting seat. The negative pressure starts from -0.2 bar, is stepped up to -0.4 bar, and is maintained at -0.4 bar for 50 to 60 minutes; In the sintering stage, the negative pressure is quickly increased to -0.8 bar and remains constant in the soaking stage; In the cooling stage, stop suction, and the negative pressure is gradually reduced to atmospheric pressure to avoid cracking caused by thermal stress; The negative pressure suction is used to discharge the heating residual substances of various adhesives.

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